diff --git a/utils/yangutils/src/test/resources/interfileietf/ietf-inet-types.yang b/utils/yangutils/src/test/resources/interfileietf/ietf-inet-types.yang
new file mode 100644
index 0000000..2b7ed38
--- /dev/null
+++ b/utils/yangutils/src/test/resources/interfileietf/ietf-inet-types.yang
@@ -0,0 +1,454 @@
+  module ietf-inet-types {
+
+    yang-version 1;
+
+    namespace
+      "urn:ietf:params:xml:ns:yang:ietf-inet-types";
+
+    prefix inet;
+
+    organization
+      "IETF NETMOD (NETCONF Data Modeling Language) Working Group";
+
+    contact
+      "WG Web:   <http://tools.ietf.org/wg/netmod/>
+    WG List:  <mailto:netmod@ietf.org>
+
+    WG Chair: David Kessens
+              <mailto:david.kessens@nsn.com>
+
+    WG Chair: Juergen Schoenwaelder
+              <mailto:j.schoenwaelder@jacobs-university.de>
+
+    Editor:   Juergen Schoenwaelder
+              <mailto:j.schoenwaelder@jacobs-university.de>";
+
+    description
+      "This module contains a collection of generally useful derived
+    YANG data types for Internet addresses and related things.
+
+    Copyright (c) 2013 IETF Trust and the persons identified as
+    authors of the code.  All rights reserved.
+
+    Redistribution and use in source and binary forms, with or
+    without modification, is permitted pursuant to, and subject
+    to the license terms contained in, the Simplified BSD License
+    set forth in Section 4.c of the IETF Trust's Legal Provisions
+    Relating to IETF Documents
+    (http://trustee.ietf.org/license-info).
+
+    This version of this YANG module is part of RFC 6991; see
+    the RFC itself for full legal notices.";
+
+    revision "2013-07-15" {
+      description
+        "This revision adds the following new data types:
+      - ip-address-no-zone
+      - ipv4-address-no-zone
+      - ipv6-address-no-zone";
+      reference
+        "RFC 6991: Common YANG Data Types";
+
+    }
+
+    revision "2010-09-24" {
+      description "Initial revision.";
+      reference
+        "RFC 6021: Common YANG Data Types";
+
+    }
+
+
+    typedef ip-version {
+      type enumeration {
+        enum "unknown" {
+          value 0;
+          description
+            "An unknown or unspecified version of the Internet
+          protocol.";
+        }
+        enum "ipv4" {
+          value 1;
+          description
+            "The IPv4 protocol as defined in RFC 791.";
+        }
+        enum "ipv6" {
+          value 2;
+          description
+            "The IPv6 protocol as defined in RFC 2460.";
+        }
+      }
+      description
+        "This value represents the version of the IP protocol.
+
+      In the value set and its semantics, this type is equivalent
+      to the InetVersion textual convention of the SMIv2.";
+      reference
+        "RFC  791: Internet Protocol
+         RFC 2460: Internet Protocol, Version 6 (IPv6) Specification
+         RFC 4001: Textual Conventions for Internet Network Addresses";
+
+    }
+
+    typedef dscp {
+      type uint8 {
+        range "0..63";
+      }
+      description
+        "The dscp type represents a Differentiated Services Code Point
+      that may be used for marking packets in a traffic stream.
+      In the value set and its semantics, this type is equivalent
+      to the Dscp textual convention of the SMIv2.";
+      reference
+        "RFC 3289: Management Information Base for the Differentiated
+        	  Services Architecture
+         RFC 2474: Definition of the Differentiated Services Field
+        	  (DS Field) in the IPv4 and IPv6 Headers
+         RFC 2780: IANA Allocation Guidelines For Values In
+        	  the Internet Protocol and Related Headers";
+
+    }
+
+    typedef ipv6-flow-label {
+      type uint32 {
+        range "0..1048575";
+      }
+      description
+        "The ipv6-flow-label type represents the flow identifier or Flow
+      Label in an IPv6 packet header that may be used to
+      discriminate traffic flows.
+
+      In the value set and its semantics, this type is equivalent
+      to the IPv6FlowLabel textual convention of the SMIv2.";
+      reference
+        "RFC 3595: Textual Conventions for IPv6 Flow Label
+         RFC 2460: Internet Protocol, Version 6 (IPv6) Specification";
+
+    }
+
+    typedef port-number {
+      type uint16 {
+        range "0..65535";
+      }
+      description
+        "The port-number type represents a 16-bit port number of an
+      Internet transport-layer protocol such as UDP, TCP, DCCP, or
+      SCTP.  Port numbers are assigned by IANA.  A current list of
+      all assignments is available from <http://www.iana.org/>.
+
+      Note that the port number value zero is reserved by IANA.  In
+      situations where the value zero does not make sense, it can
+      be excluded by subtyping the port-number type.
+      In the value set and its semantics, this type is equivalent
+      to the InetPortNumber textual convention of the SMIv2.";
+      reference
+        "RFC  768: User Datagram Protocol
+         RFC  793: Transmission Control Protocol
+         RFC 4960: Stream Control Transmission Protocol
+         RFC 4340: Datagram Congestion Control Protocol (DCCP)
+         RFC 4001: Textual Conventions for Internet Network Addresses";
+
+    }
+
+    typedef as-number {
+      type uint32;
+      description
+        "The as-number type represents autonomous system numbers
+      which identify an Autonomous System (AS).  An AS is a set
+      of routers under a single technical administration, using
+      an interior gateway protocol and common metrics to route
+      packets within the AS, and using an exterior gateway
+      protocol to route packets to other ASes.  IANA maintains
+      the AS number space and has delegated large parts to the
+      regional registries.
+
+      Autonomous system numbers were originally limited to 16
+      bits.  BGP extensions have enlarged the autonomous system
+      number space to 32 bits.  This type therefore uses an uint32
+      base type without a range restriction in order to support
+      a larger autonomous system number space.
+
+      In the value set and its semantics, this type is equivalent
+      to the InetAutonomousSystemNumber textual convention of
+      the SMIv2.";
+      reference
+        "RFC 1930: Guidelines for creation, selection, and registration
+        	  of an Autonomous System (AS)
+         RFC 4271: A Border Gateway Protocol 4 (BGP-4)
+         RFC 4001: Textual Conventions for Internet Network Addresses
+         RFC 6793: BGP Support for Four-Octet Autonomous System (AS)
+        	  Number Space";
+
+    }
+
+    typedef ip-address {
+      type union {
+        type ipv4-address;
+        type ipv6-address;
+      }
+      description
+        "The ip-address type represents an IP address and is IP
+      version neutral.  The format of the textual representation
+      implies the IP version.  This type supports scoped addresses
+      by allowing zone identifiers in the address format.";
+      reference
+        "RFC 4007: IPv6 Scoped Address Architecture";
+
+    }
+
+    typedef ipv4-address {
+      type string {
+        pattern
+          '(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(%[\p{N}\p{L}]+)?';
+      }
+      description
+        "The ipv4-address type represents an IPv4 address in
+       dotted-quad notation.  The IPv4 address may include a zone
+       index, separated by a % sign.
+
+       The zone index is used to disambiguate identical address
+       values.  For link-local addresses, the zone index will
+       typically be the interface index number or the name of an
+       interface.  If the zone index is not present, the default
+       zone of the device will be used.
+
+       The canonical format for the zone index is the numerical
+       format";
+    }
+
+    typedef ipv6-address {
+      type string {
+        pattern
+          '((:|[0-9a-fA-F]{0,4}):)([0-9a-fA-F]{0,4}:){0,5}((([0-9a-fA-F]{0,4}:)?(:|[0-9a-fA-F]{0,4}))|(((25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])))(%[\p{N}\p{L}]+)?';
+        pattern
+          '(([^:]+:){6}(([^:]+:[^:]+)|(.*\..*)))|((([^:]+:)*[^:]+)?::(([^:]+:)*[^:]+)?)(%.+)?';
+      }
+      description
+        "The ipv6-address type represents an IPv6 address in full,
+      mixed, shortened, and shortened-mixed notation.  The IPv6
+      address may include a zone index, separated by a % sign.
+
+      The zone index is used to disambiguate identical address
+      values.  For link-local addresses, the zone index will
+      typically be the interface index number or the name of an
+      interface.  If the zone index is not present, the default
+      zone of the device will be used.
+
+
+
+      The canonical format of IPv6 addresses uses the textual
+      representation defined in Section 4 of RFC 5952.  The
+      canonical format for the zone index is the numerical
+      format as described in Section 11.2 of RFC 4007.";
+      reference
+        "RFC 4291: IP Version 6 Addressing Architecture
+         RFC 4007: IPv6 Scoped Address Architecture
+         RFC 5952: A Recommendation for IPv6 Address Text
+        	  Representation";
+
+    }
+
+    typedef ip-address-no-zone {
+      type union {
+        type ipv4-address-no-zone;
+        type ipv6-address-no-zone;
+      }
+      description
+        "The ip-address-no-zone type represents an IP address and is
+      IP version neutral.  The format of the textual representation
+      implies the IP version.  This type does not support scoped
+      addresses since it does not allow zone identifiers in the
+      address format.";
+      reference
+        "RFC 4007: IPv6 Scoped Address Architecture";
+
+    }
+
+    typedef ipv4-address-no-zone {
+      type ipv4-address {
+        pattern '[0-9\.]*';
+      }
+      description
+        "An IPv4 address without a zone index.  This type, derived from
+       ipv4-address, may be used in situations where the zone is
+       known from the context and hence no zone index is needed.";
+    }
+
+    typedef ipv6-address-no-zone {
+      type ipv6-address {
+        pattern '[0-9a-fA-F:\.]*';
+      }
+      description
+        "An IPv6 address without a zone index.  This type, derived from
+       ipv6-address, may be used in situations where the zone is
+       known from the context and hence no zone index is needed.";
+      reference
+        "RFC 4291: IP Version 6 Addressing Architecture
+         RFC 4007: IPv6 Scoped Address Architecture
+         RFC 5952: A Recommendation for IPv6 Address Text
+        	  Representation";
+
+    }
+
+    typedef ip-prefix {
+      type union {
+        type ipv4-prefix;
+        type ipv6-prefix;
+      }
+      description
+        "The ip-prefix type represents an IP prefix and is IP
+      version neutral.  The format of the textual representations
+      implies the IP version.";
+    }
+
+    typedef ipv4-prefix {
+      type string {
+        pattern
+          '(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])/(([0-9])|([1-2][0-9])|(3[0-2]))';
+      }
+      description
+        "The ipv4-prefix type represents an IPv4 address prefix.
+      The prefix length is given by the number following the
+      slash character and must be less than or equal to 32.
+
+      A prefix length value of n corresponds to an IP address
+      mask that has n contiguous 1-bits from the most
+      significant bit (MSB) and all other bits set to 0.
+
+      The canonical format of an IPv4 prefix has all bits of
+      the IPv4 address set to zero that are not part of the
+      IPv4 prefix.";
+    }
+
+    typedef ipv6-prefix {
+      type string {
+        pattern
+          '((:|[0-9a-fA-F]{0,4}):)([0-9a-fA-F]{0,4}:){0,5}((([0-9a-fA-F]{0,4}:)?(:|[0-9a-fA-F]{0,4}))|(((25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])))(/(([0-9])|([0-9]{2})|(1[0-1][0-9])|(12[0-8])))';
+        pattern
+          '(([^:]+:){6}(([^:]+:[^:]+)|(.*\..*)))|((([^:]+:)*[^:]+)?::(([^:]+:)*[^:]+)?)(/.+)';
+      }
+      description
+        "The ipv6-prefix type represents an IPv6 address prefix.
+      The prefix length is given by the number following the
+      slash character and must be less than or equal to 128.
+
+      A prefix length value of n corresponds to an IP address
+      mask that has n contiguous 1-bits from the most
+      significant bit (MSB) and all other bits set to 0.
+
+      The IPv6 address should have all bits that do not belong
+      to the prefix set to zero.
+
+      The canonical format of an IPv6 prefix has all bits of
+      the IPv6 address set to zero that are not part of the
+      IPv6 prefix.  Furthermore, the IPv6 address is represented
+      as defined in Section 4 of RFC 5952.";
+      reference
+        "RFC 5952: A Recommendation for IPv6 Address Text
+        	  Representation";
+
+    }
+
+    typedef domain-name {
+      type string {
+        length "1..253";
+        pattern
+          '((([a-zA-Z0-9_]([a-zA-Z0-9\-_]){0,61})?[a-zA-Z0-9]\.)*([a-zA-Z0-9_]([a-zA-Z0-9\-_]){0,61})?[a-zA-Z0-9]\.?)|\.';
+      }
+      description
+        "The domain-name type represents a DNS domain name.  The
+      name SHOULD be fully qualified whenever possible.
+
+      Internet domain names are only loosely specified.  Section
+      3.5 of RFC 1034 recommends a syntax (modified in Section
+      2.1 of RFC 1123).  The pattern above is intended to allow
+      for current practice in domain name use, and some possible
+      future expansion.  It is designed to hold various types of
+      domain names, including names used for A or AAAA records
+      (host names) and other records, such as SRV records.  Note
+      that Internet host names have a stricter syntax (described
+      in RFC 952) than the DNS recommendations in RFCs 1034 and
+      1123, and that systems that want to store host names in
+      schema nodes using the domain-name type are recommended to
+      adhere to this stricter standard to ensure interoperability.
+
+      The encoding of DNS names in the DNS protocol is limited
+      to 255 characters.  Since the encoding consists of labels
+      prefixed by a length bytes and there is a trailing NULL
+      byte, only 253 characters can appear in the textual dotted
+      notation.
+
+      The description clause of schema nodes using the domain-name
+      type MUST describe when and how these names are resolved to
+      IP addresses.  Note that the resolution of a domain-name value
+      may require to query multiple DNS records (e.g., A for IPv4
+      and AAAA for IPv6).  The order of the resolution process and
+      which DNS record takes precedence can either be defined
+      explicitly or may depend on the configuration of the
+      resolver.
+
+      Domain-name values use the US-ASCII encoding.  Their canonical
+      format uses lowercase US-ASCII characters.  Internationalized
+      domain names MUST be A-labels as per RFC 5890.";
+      reference
+        "RFC  952: DoD Internet Host Table Specification
+         RFC 1034: Domain Names - Concepts and Facilities
+         RFC 1123: Requirements for Internet Hosts -- Application
+        	  and Support
+         RFC 2782: A DNS RR for specifying the location of services
+        	  (DNS SRV)
+         RFC 5890: Internationalized Domain Names in Applications
+        	  (IDNA): Definitions and Document Framework";
+
+    }
+
+    typedef host {
+      type union {
+        type ip-address;
+        type domain-name;
+      }
+      description
+        "The host type represents either an IP address or a DNS
+      domain name.";
+    }
+
+    typedef uri {
+      type string;
+      description
+        "The uri type represents a Uniform Resource Identifier
+      (URI) as defined by STD 66.
+
+      Objects using the uri type MUST be in US-ASCII encoding,
+      and MUST be normalized as described by RFC 3986 Sections
+      6.2.1, 6.2.2.1, and 6.2.2.2.  All unnecessary
+      percent-encoding is removed, and all case-insensitive
+      characters are set to lowercase except for hexadecimal
+      digits, which are normalized to uppercase as described in
+      Section 6.2.2.1.
+
+      The purpose of this normalization is to help provide
+      unique URIs.  Note that this normalization is not
+      sufficient to provide uniqueness.  Two URIs that are
+      textually distinct after this normalization may still be
+      equivalent.
+
+      Objects using the uri type may restrict the schemes that
+      they permit.  For example, 'data:' and 'urn:' schemes
+      might not be appropriate.
+
+      A zero-length URI is not a valid URI.  This can be used to
+      express 'URI absent' where required.
+
+      In the value set and its semantics, this type is equivalent
+      to the Uri SMIv2 textual convention defined in RFC 5017.";
+      reference
+        "RFC 3986: Uniform Resource Identifier (URI): Generic Syntax
+         RFC 3305: Report from the Joint W3C/IETF URI Planning Interest
+        	  Group: Uniform Resource Identifiers (URIs), URLs,
+        	  and Uniform Resource Names (URNs): Clarifications
+        	  and Recommendations
+         RFC 5017: MIB Textual Conventions for Uniform Resource
+        	  Identifiers (URIs)";
+
+    }
+  }  // module ietf-inet-types
diff --git a/utils/yangutils/src/test/resources/interfileietf/ietf-network-topology.yang b/utils/yangutils/src/test/resources/interfileietf/ietf-network-topology.yang
new file mode 100644
index 0000000..10c8fb9
--- /dev/null
+++ b/utils/yangutils/src/test/resources/interfileietf/ietf-network-topology.yang
@@ -0,0 +1,260 @@
+ module ietf-network-topology {
+   yang-version 1;
+   namespace "urn:ietf:params:xml:ns:yang:ietf-network-topology";
+   prefix lnk;
+
+   import ietf-inet-types {
+     prefix inet;
+   }
+   import ietf-network {
+     prefix nd;
+   }
+
+   organization
+     "IETF I2RS (Interface to the Routing System) Working Group";
+
+   contact
+     "WG Web:    <http://tools.ietf.org/wg/i2rs/>
+      WG List:   <mailto:i2rs@ietf.org>
+
+      WG Chair:  Susan Hares
+                 <mailto:shares@ndzh.com>
+
+      WG Chair:  Jeffrey Haas
+                 <mailto:jhaas@pfrc.org>
+
+      Editor:    Alexander Clemm
+                 <mailto:alex@cisco.com>
+
+      Editor:    Jan Medved
+                 <mailto:jmedved@cisco.com>
+
+      Editor:    Robert Varga
+                 <mailto:rovarga@cisco.com>
+
+      Editor:    Tony Tkacik
+                 <mailto:ttkacik@cisco.com>
+
+      Editor:    Nitin Bahadur
+                 <mailto:nitin_bahadur@yahoo.com>
+
+      Editor:    Hariharan Ananthakrishnan
+                 <mailto:hari@packetdesign.com>";
+
+   description
+     "This module defines a common base model for network topology,
+      augmenting the base network model with links to connect nodes,
+      as well as termination points to terminate links on nodes.
+
+      Copyright (c) 2015 IETF Trust and the persons identified as
+      authors of the code.  All rights reserved.
+
+      Redistribution and use in source and binary forms, with or
+      without modification, is permitted pursuant to, and subject
+      to the license terms contained in, the Simplified BSD License
+      set forth in Section 4.c of the IETF Trust's Legal Provisions
+      Relating to IETF Documents
+      (http://trustee.ietf.org/license-info).
+
+      This version of this YANG module is part of
+      draft-ietf-i2rs-yang-network-topo-02;
+      see the RFC itself for full legal notices.
+
+      NOTE TO RFC EDITOR: Please replace above reference to
+      draft-ietf-i2rs-yang-network-topo-02 with RFC
+      number when published (i.e. RFC xxxx).";
+
+   revision 2015-12-08 {
+     description
+       "Initial revision.
+        NOTE TO RFC EDITOR: Please replace the following reference
+        to draft-ietf-i2rs-yang-network-topo-02 with
+        RFC number when published (i.e. RFC xxxx).";
+     reference
+       "draft-ietf-i2rs-yang-network-topo-02.";
+   }
+
+   typedef link-id {
+     type inet:uri;
+     description
+       "An identifier for a link in a topology.
+        The identifier SHOULD be chosen such that the same link in a
+        real network topology will always be identified through the
+        same identifier, even if the model is instantiated in
+            separate datastores. An implementation MAY choose to capture
+        semantics in the identifier, for example to indicate the type
+        of link and/or the type of topology that the link is a part
+        of.";
+   }
+
+   typedef tp-id {
+     type inet:uri;
+     description
+       "An identifier for termination points on a node.
+        The identifier SHOULD be chosen such that the same TP in a
+        real network topology will always be identified through the
+        same identifier, even if the model is instantiated in
+        separate datastores. An implementation MAY choose to capture
+        semantics in the identifier, for example to indicate the type
+        of TP and/or the type of node and topology that the TP is a
+        part of.";
+   }
+   grouping link-ref {
+     description
+       "References a link in a specific network.";
+     leaf link-ref {
+       type link-id;
+       description
+         "A type for an absolute reference a link instance.
+          (This type should not be used for relative references.
+          In such a case, a relative path should be used instead.)";
+     }
+     uses nd:network-ref;
+   }
+
+   grouping tp-ref {
+     description
+       "References a termination point in a specific node.";
+     leaf tp-ref {
+       type tp-id;
+       description
+         "A type for an absolute reference to a termination point.
+          (This type should not be used for relative references.
+          In such a case, a relative path should be used instead.)";
+     }
+     uses nd:node-ref;
+   }
+
+   augment "/nd:networks/nd:network" {
+     description
+       "Add links to the network model.";
+     list link {
+       key "link-id";
+       description
+         "A Network Link connects a by Local (Source) node and
+          a Remote (Destination) Network Nodes via a set of the
+          nodes' termination points.
+          As it is possible to have several links between the same
+          source and destination nodes, and as a link could
+          potentially be re-homed between termination points, to
+          ensure that we would always know to distinguish between
+          links, every link is identified by a dedicated link
+          identifier.
+          Note that a link models a point-to-point link, not a
+          multipoint link.
+          Layering dependencies on links in underlay topologies are
+          not represented as the layering information of nodes and of
+          termination points is sufficient.";
+       container source {
+         description
+           "This container holds the logical source of a particular
+            link.";
+         leaf source-node {
+           type nd:node-id;
+           mandatory true;
+           description
+             "Source node identifier, must be in same topology.";
+         }
+         leaf source-tp {
+           type tp-id;
+           description
+             "Termination point within source node that terminates
+              the link.";
+         }
+       }
+       container destination {
+         description
+           "This container holds the logical destination of a
+            particular link.";
+         leaf dest-node {
+           type nd:node-id;
+           mandatory true;
+           description
+             "Destination node identifier, must be in the same
+              network.";
+         }
+         leaf dest-tp {
+           type tp-id;
+           description
+             "Termination point within destination node that
+              terminates the link.";
+         }
+       }
+       leaf link-id {
+         type link-id;
+         description
+           "The identifier of a link in the topology.
+            A link is specific to a topology to which it belongs.";
+       }
+       list supporting-link {
+         key "network-ref link-ref";
+         description
+           "Identifies the link, or links, that this link
+            is dependent on.";
+         leaf network-ref {
+           type nd:network-id;
+           description
+             "This leaf identifies in which underlay topology
+              supporting link is present.";
+         }
+         leaf link-ref {
+           type link-id;
+           description
+             "This leaf identifies a link which is a part
+              of this link's underlay. Reference loops, in which
+              a link identifies itself as its underlay, either
+              directly or transitively, are not allowed.";
+         }
+       }
+     }
+   }
+   augment "/nd:networks/nd:network/nd:node" {
+     description
+       "Augment termination points which terminate links.
+        Termination points can ultimately be mapped to interfaces.";
+     list termination-point {
+       key "tp-id";
+       description
+         "A termination point can terminate a link.
+          Depending on the type of topology, a termination point
+          could, for example, refer to a port or an interface.";
+       leaf tp-id {
+         type tp-id;
+         description
+           "Termination point identifier.";
+       }
+       list supporting-termination-point {
+         key "network-ref node-ref tp-ref";
+         description
+           "The leaf list identifies any termination points that
+            the termination point is dependent on, or maps onto.
+            Those termination points will themselves be contained
+            in a supporting node.
+            This dependency information can be inferred from
+            the dependencies between links.  For this reason,
+            this item is not separately configurable.  Hence no
+            corresponding constraint needs to be articulated.
+            The corresponding information is simply provided by the
+            implementing system.";
+         leaf network-ref {
+           type nd:network-id;
+           description
+             "This leaf identifies in which topology the
+              supporting termination point is present.";
+         }
+         leaf node-ref {
+           type nd:node-id;
+           description
+             "This leaf identifies in which node the supporting
+              termination point is present.";
+         }
+         leaf tp-ref {
+           type tp-id;
+           description
+             "Reference to the underlay node, must be in a
+              different topology";
+         }
+       }
+     }
+   }
+ }
diff --git a/utils/yangutils/src/test/resources/interfileietf/ietf-network.yang b/utils/yangutils/src/test/resources/interfileietf/ietf-network.yang
new file mode 100644
index 0000000..9dbe38f
--- /dev/null
+++ b/utils/yangutils/src/test/resources/interfileietf/ietf-network.yang
@@ -0,0 +1,200 @@
+   module ietf-network {
+     yang-version 1;
+     namespace "urn:ietf:params:xml:ns:yang:ietf-network";
+     prefix nd;
+
+     import ietf-inet-types {
+       prefix inet;
+     }
+
+     organization
+       "IETF I2RS (Interface to the Routing System) Working Group";
+
+     contact
+       "WG Web:    <http://tools.ietf.org/wg/i2rs/>
+        WG List:   <mailto:i2rs@ietf.org>
+
+        WG Chair:  Susan Hares
+                   <mailto:shares@ndzh.com>
+
+        WG Chair:  Jeffrey Haas
+                   <mailto:jhaas@pfrc.org>
+
+        Editor:    Alexander Clemm
+                   <mailto:alex@cisco.com>
+
+        Editor:    Jan Medved
+                   <mailto:jmedved@cisco.com>
+
+        Editor:    Robert Varga
+                   <mailto:rovarga@cisco.com>
+
+        Editor:    Tony Tkacik
+                   <mailto:ttkacik@cisco.com>
+
+        Editor:    Nitin Bahadur
+                   <mailto:nitin_bahadur@yahoo.com>
+
+        Editor:    Hariharan Ananthakrishnan
+                   <mailto:hari@packetdesign.com>";
+
+     description
+       "This module defines a common base model for a collection
+        of nodes in a network. Node definitions are further used
+        in network topologies and inventories.
+
+        Copyright (c) 2015 IETF Trust and the persons identified as
+        authors of the code.  All rights reserved.
+
+        Redistribution and use in source and binary forms, with or
+        without modification, is permitted pursuant to, and subject
+        to the license terms contained in, the Simplified BSD License
+        set forth in Section 4.c of the IETF Trust's Legal Provisions
+        Relating to IETF Documents
+        (http://trustee.ietf.org/license-info).
+
+        This version of this YANG module is part of
+        draft-ietf-i2rs-yang-network-topo-02;
+        see the RFC itself for full legal notices.
+
+        NOTE TO RFC EDITOR: Please replace above reference to
+        draft-ietf-i2rs-yang-network-topo-02 with RFC
+        number when published (i.e. RFC xxxx).";
+
+     revision 2015-12-08 {
+       description
+         "Initial revision.
+          NOTE TO RFC EDITOR: Please replace the following reference
+          to draft-ietf-i2rs-yang-network-topo-02 with
+          RFC number when published (i.e. RFC xxxx).";
+       reference
+         "draft-ietf-i2rs-yang-network-topo-02";
+     }
+
+     typedef node-id {
+       type inet:uri;
+       description
+         "Identifier for a node.";
+     }
+
+     typedef network-id {
+       type inet:uri;
+       description
+         "Identifier for a network.";
+     }
+     grouping network-ref {
+       description
+         "Contains the information necessary to reference a network,
+          for example an underlay network.";
+       leaf network-ref {
+         type network-id;
+         description
+           "Used to reference a network, for example an underlay
+            network.";
+       }
+     }
+
+     grouping node-ref {
+       description
+         "Contains the information necessary to reference a node.";
+       leaf node-ref {
+         type node-id;
+         description
+           "Used to reference a node.
+            Nodes are identified relative to the network they are
+            contained in.";
+       }
+       uses network-ref;
+     }
+
+     container networks {
+       description
+         "Serves as top-level container for a list of networks.";
+       list network {
+         key "network-id";
+         description
+           "Describes a network.
+            A network typically contains an inventory of nodes,
+            topological information (augmented through
+            network-topology model), as well as layering
+            information.";
+         container network-types {
+           description
+             "Serves as an augmentation target.
+              The network type is indicated through corresponding
+              presence containers augmented into this container.";
+         }
+         leaf network-id {
+           type network-id;
+           description
+             "Identifies a network.";
+         }
+         list supporting-network {
+           key "network-ref";
+           description
+             "An underlay network, used to represent layered network
+              topologies.";
+           leaf network-ref {
+             type network-id;
+             description
+               "References the underlay network.";
+           }
+         }
+         list node {
+           key "node-id";
+           description
+             "The inventory of nodes of this network.";
+           leaf node-id {
+             type node-id;
+             description
+               "Identifies a node uniquely within the containing
+                network.";
+           }
+           list supporting-node {
+             key "network-ref node-ref";
+             description
+               "Represents another node, in an underlay network, that
+                this node is supported by.  Used to represent layering
+                structure.";
+             leaf network-ref {
+               type network-id;
+               description
+                 "References the underlay network that the
+                  underlay node is part of.";
+             }
+             leaf node-ref {
+               type node-id;
+               description
+                 "References the underlay node itself.";
+             }
+           }
+         }
+       }
+     }
+     container networks-state {
+       config false;
+       description
+         "Serves as top-level container for a list of state information
+          for networks";
+       list network {
+         key "network-ref";
+         description
+           "Data nodes representing operational data and state of
+            networks.
+            An instance is automatically created for every network
+            in the corresponding list under the networks container.";
+         uses network-ref;
+         leaf server-provided {
+           type boolean;
+           description
+             "Indicates whether the information concerning this
+              particular network is populated by the server
+              (server-provided true, the general case for network
+              information discovered from the server),
+              or whether it is configured by a client
+              (server-provided true, possible e.g. for
+              service overlays managed through a controller).";
+         }
+       }
+     }
+   }
diff --git a/utils/yangutils/src/test/resources/interfileietf/ietf-schedule.yang b/utils/yangutils/src/test/resources/interfileietf/ietf-schedule.yang
new file mode 100644
index 0000000..b9f7297
--- /dev/null
+++ b/utils/yangutils/src/test/resources/interfileietf/ietf-schedule.yang
@@ -0,0 +1,64 @@
+   module ietf-schedule {
+     yang-version 1;
+     namespace "urn:ietf:params:xml:ns:yang:ietf-schedule";
+     // replace with IANA namespace when assigned
+
+     prefix "sch";
+
+     import ietf-yang-types {
+       prefix "yang";
+     }
+
+     organization "TBD";
+     contact "TBD";
+     description
+       "The model allows time scheduling parameters to be specified.";
+
+     revision "2016-03-01" {
+       description "Initial revision";
+       reference "TBD";
+     }
+
+     /*
+      * Groupings
+      */
+
+     grouping schedules {
+       description
+         "A list of schedules defining when a particular
+          configuration takes effect.";
+       container schedules {
+         description
+           "Container of a schedule list defining when a particular
+            configuration takes effect.";
+         list schedule {
+           key "schedule-id";
+           description "A list of schedule elements.";
+
+           leaf schedule-id {
+             type uint32;
+             description "Identifies the schedule element.";
+           }
+           leaf start {
+             type yang:date-and-time;
+             description "Start time.";
+           }
+           leaf schedule-duration {
+             type string {
+               pattern
+                 'P(\d+Y)?(\d+M)?(\d+W)?(\d+D)?T(\d+H)?(\d+M)?(\d+S)?';
+             }
+             description "Schedule duration in ISO 8601 format.";
+           }
+           leaf repeat-interval {
+             type string {
+               pattern
+                 'R\d*/P(\d+Y)?(\d+M)?(\d+W)?(\d+D)?T(\d+H)?(\d+M)?'
+                 + '(\d+S)?';
+             }
+             description "Repeat interval in ISO 8601 format.";
+           }
+         }
+       }
+     } // schedules
+   }
diff --git a/utils/yangutils/src/test/resources/interfileietf/ietf-te-topology.yang b/utils/yangutils/src/test/resources/interfileietf/ietf-te-topology.yang
new file mode 100644
index 0000000..849828f
--- /dev/null
+++ b/utils/yangutils/src/test/resources/interfileietf/ietf-te-topology.yang
@@ -0,0 +1,1730 @@
+   module ietf-te-topology {
+     yang-version 1;
+     namespace "urn:ietf:params:xml:ns:yang:ietf-te-topology";
+     // replace with IANA namespace when assigned
+
+     prefix "tet";
+
+     import ietf-inet-types {
+       prefix "inet";
+     }
+
+     import ietf-schedule {
+       prefix "sch";
+     }
+
+     import ietf-te-types {
+       prefix "te-types";
+     }
+
+     import ietf-network {
+       prefix "nw";
+     }
+
+     import ietf-network-topology {
+       prefix "nt";
+     }
+
+     organization
+       "Traffic Engineering Architecture and Signaling (TEAS)
+        Working Group";
+
+     contact
+       "WG Web:   <http://tools.ietf.org/wg/teas/>
+        WG List:  <mailto:teas@ietf.org>
+
+        WG Chair: Lou Berger
+                  <mailto:lberger@labn.net>
+
+        WG Chair: Vishnu Pavan Beeram
+                  <mailto:vbeeram@juniper.net>
+
+        Editor:   Xufeng Liu
+                  <mailto:xliu@kuatrotech.com>
+
+        Editor:   Igor Bryskin
+                  <mailto:Igor.Bryskin@huawei.com>
+
+        Editor:   Vishnu Pavan Beeram
+                  <mailto:vbeeram@juniper.net>
+
+        Editor:   Tarek Saad
+                  <mailto:tsaad@cisco.com>
+
+        Editor:   Himanshu Shah
+                  <mailto:hshah@ciena.com>
+
+        Editor:   Oscar Gonzalez De Dios
+                  <mailto:oscar.gonzalezdedios@telefonica.com>";
+
+     description "TE topology model";
+
+     revision "2016-03-17" {
+       description "Initial revision";
+       reference "TBD";
+     }
+
+     /*
+      * Features
+      */
+
+     /*feature configuration-schedule {
+       description
+         "This feature indicates that the system supports
+          configuration scheduling.";
+     }
+
+     feature te-topology-hierarchy {
+       description
+         "This feature indicates that the system allows underlay
+          and/or overlay TE topology hierarchy.";
+     }
+
+     feature te-performance-metric {
+       description
+         "This feature indicates that the system supports
+          TE performance metric defined in
+          RFC7471: OSPF Traffic Engineering (TE) Metric Extensions.";
+     }
+
+     feature template {
+       description
+         "This feature indicates that the system supports
+          template configuration.";
+     }*/
+
+     /*
+      * Typedefs
+      */
+     typedef performance-metric-normality {
+       type enumeration {
+         enum "unknown" {
+           value 0;
+           description
+             "Unknown.";
+         }
+         enum "normal" {
+           value 1;
+           description
+             "Normal.";
+         }
+         enum "abnormal" {
+           value 2;
+           description
+             "Abnormal. The anomalous bit is set.";
+         }
+       }
+       description
+         "Indicates whether a performance metric is normal, abnormal, or
+          unknown.";
+       reference
+         "RFC7471: OSPF Traffic Engineering (TE) Metric Extensions.";
+     }
+
+     typedef te-admin-status {
+       type enumeration {
+         enum up {
+           description
+             "Enabled.";
+         }
+         enum down {
+           description
+             "Disabled.";
+         }
+         enum testing {
+           description
+             "In some test mode.";
+         }
+         enum preparing-maintenance {
+           description
+             "Resource is disabled in the control plane to prepare for
+              graceful shutdown for maintenance purposes.";
+           reference
+             "RFC5817: Graceful Shutdown in MPLS and Generalized MPLS
+              Traffic Engineering Networks";
+         }
+         enum maintenance {
+           description
+             "Resource is disabled in the data plane for maintenance
+              purposes.";
+         }
+       }
+       description
+         "Defines a type representing the administrative status of
+          a TE resource.";
+     }
+     typedef te-global-id {
+       type uint32;
+       description
+         "An identifier to uniquely identify an operator, which can be
+          either a provider or a client.
+          The definition of this type is taken from RFC6370 and RFC5003.
+          This attribute type is used solely to provide a globally
+          unique context for TE topologies.";
+     }
+
+     typedef te-link-access-type {
+       type enumeration {
+         enum point-to-point {
+           description
+             "The link is point-to-point.";
+         }
+         enum multi-access {
+           description
+             "The link is multi-access, including broacast and NBMA.";
+         }
+       }
+       description
+         "Defines a type representing the access type of a TE link.";
+       reference
+         "RFC3630: Traffic Engineering (TE) Extensions to OSPF
+          Version 2.";
+     }
+
+     typedef te-node-id {
+       type inet:ip-address;
+       description
+         "An identifier for a node in a topology.
+          The identifier is represented as an IPv4 or IPv6 address.
+          This attribute is mapped to Router ID in
+          RFC3630, RFC5329, RFC5305, and RFC 6119.";
+     }
+
+     typedef te-oper-status {
+       type enumeration {
+         enum up {
+           description
+           "Operational up.";
+         }
+         enum down {
+           description
+           "Operational down.";
+         }
+         enum testing {
+           description
+           "In some test mode.";
+         }
+         enum unknown {
+           description
+           "Status cannot be determined for some reason.";
+         }
+         enum preparing-maintenance {
+           description
+             "Resource is disabled in the control plane to prepare for
+              graceful shutdown for maintenance purposes.";
+           reference
+             "RFC5817: Graceful Shutdown in MPLS and Generalized MPLS
+              Traffic Engineering Networks";
+         }
+         enum maintenance {
+           description
+             "Resource is disabled in the data plane for maintenance
+              purposes.";
+         }
+       }
+       description
+         "Defines a type representing the operational status of
+          a TE resource.";
+     }
+
+     typedef te-recovery-status {
+       type enumeration {
+         enum normal {
+           description
+             "Both the recovery and working spans are fully
+              allocated and active, data traffic is being
+              transported over (or selected from) the working
+              span, and no trigger events are reported.";
+         }
+         enum recovery-started {
+           description
+             "The recovery action has been started, but not completed.";
+         }
+         enum recovery-succeeded {
+           description
+             "The recovery action has succeeded. The working span has
+              reported a failure/degrade condition and the user traffic
+              is being transported (or selected) on the recovery span.";
+         }
+         enum recovery-failed {
+           description
+             "The recovery action has failed.";
+         }
+         enum reversion-started {
+           description
+             "The reversion has started.";
+         }
+         enum reversion-failed {
+           description
+             "The reversion has failed.";
+         }
+         enum recovery-unavailable {
+           description
+             "The recovery is unavailable -- either as a result of an
+              operator Lockout command or a failure condition detected
+              on the recovery span.";
+         }
+         enum recovery-admin {
+           description
+             "The operator has issued a command switching the user
+              traffic to the recovery span.";
+         }
+         enum wait-to-restore {
+           description
+             "The recovery domain is recovering from a failuer/degrade
+              condition on the working span that is being controlled by
+              the Wait-to-Restore (WTR) timer.";
+         }
+       }
+       description
+         "Defines the status of a recovery action.";
+       reference
+         "RFC4427: Recovery (Protection and Restoration) Terminology
+          for Generalized Multi-Protocol Label Switching (GMPLS).
+          RFC6378: MPLS Transport Profile (MPLS-TP) Linear Protection";
+     }
+
+     typedef te-template-name {
+       type string {
+         pattern '/?([a-zA-Z0-9\-_.]+)(/[a-zA-Z0-9\-_.]+)*';
+       }
+       description
+         "A type for the name of a TE node template or TE link
+          template.";
+     }
+
+     typedef te-topology-event-type {
+       type enumeration {
+         enum "add" {
+           value 0;
+           description
+             "A TE node or te-link has been added.";
+         }
+         enum "remove" {
+           value 1;
+           description
+             "A TE node or te-link has been removed.";
+         }
+         enum "update" {
+           value 2;
+           description
+             "A TE node or te-link has been updated.";
+         }
+       }
+       description "TE  Event type for notifications";
+     } // te-topology-event-type
+     typedef te-topology-id {
+       type string {
+         pattern '/?([a-zA-Z0-9\-_.]+)(/[a-zA-Z0-9\-_.]+)*';
+       }
+       description
+         "An identifier for a topology.";
+     }
+
+     typedef te-tp-id {
+       type union {
+         type uint32;          // Unnumbered
+         type inet:ip-address; // IPv4 or IPv6 address
+       }
+       description
+         "An identifier for a TE link endpoint on a node.
+          This attribute is mapped to local or remote link identifier in
+          RFC3630 and RFC5305.";
+     }
+
+     /*
+      * Identities
+      */
+
+     /*
+      * Groupings
+      */
+     grouping information-source-attributes {
+       description
+         "The attributes identifying source that has provided the
+          related information, and the source credibility.";
+       leaf information-source {
+         type enumeration {
+           enum "unknown" {
+             description "The source is unknown.";
+           }
+           enum "locally-configured" {
+             description "Configured entity.";
+           }
+           enum "ospfv2" {
+             description "OSPFv2.";
+           }
+           enum "ospfv3" {
+             description "OSPFv3.";
+           }
+           enum "isis" {
+             description "ISIS.";
+           }
+           enum "system-processed" {
+             description "System processed entity.";
+           }
+           enum "other" {
+             description "Other source.";
+           }
+         }
+         description
+           "Indicates the source of the information.";
+       }
+       container information-source-state {
+         description
+           "The container contains state attributes related to
+            the information source.";
+         leaf credibility-preference {
+           type uint16;
+           description
+             "The preference value to calculate the traffic
+              engineering database credibility value used for
+              tie-break selection between different
+              information-source values.
+              Higher value is more preferable.";
+         }
+         container topology {
+           description
+             "When the information is processed by the system,
+              the attributes in this container indicate which topology
+              is used to process to generate the result information.";
+           uses te-topology-ref;
+         } // topology
+         leaf routing-instance {
+           type string;
+           description
+             "When applicable, this is the name of a routing instance
+              from which the information is learned.";
+         } // routing-information
+       }
+     } // information-source-attributes
+
+     grouping performance-metric-attributes {
+       description
+         "Link performance information in real time.";
+       reference
+         "RFC7471: OSPF Traffic Engineering (TE) Metric Extensions.";
+       leaf unidirectional-delay {
+         type uint32 {
+           range 0..16777215;
+         }
+         description "Delay or latency in micro seconds.";
+       }
+       leaf unidirectional-min-delay {
+         type uint32 {
+           range 0..16777215;
+         }
+         description "Minimum delay or latency in micro seconds.";
+       }
+       leaf unidirectional-max-delay {
+         type uint32 {
+           range 0..16777215;
+         }
+         description "Maximum delay or latency in micro seconds.";
+       }
+       leaf unidirectional-delay-variation {
+         type uint32 {
+           range 0..16777215;
+         }
+         description "Delay variation in micro seconds.";
+       }
+       leaf unidirectional-packet-loss {
+         type decimal64 {
+           /*fraction-digits 6;
+           range "0 .. 50.331642";*/
+         }
+         description
+           "Packet loss as a percentage of the total traffic sent
+            over a configurable interval. The finest precision is
+            0.000003%.";
+       }
+       leaf unidirectional-residual-bandwidth {
+         type decimal64 {
+           /*fraction-digits 2;*/
+         }
+         description
+           "Residual bandwidth that subtracts tunnel
+            reservations from Maximum Bandwidth (or link capacity)
+            [RFC3630] and provides an aggregated remainder across QoS
+            classes.";
+       }
+       leaf unidirectional-available-bandwidth {
+         type decimal64 {
+           /*fraction-digits 2;*/
+         }
+         description
+           "Available bandwidth that is defined to be residual
+            bandwidth minus the measured bandwidth used for the
+            actual forwarding of non-RSVP-TE LSP packets.  For a
+            bundled link, available bandwidth is defined to be the
+            sum of the component link available bandwidths.";
+       }
+       leaf unidirectional-utilized-bandwidth {
+         type decimal64 {
+           /*fraction-digits 2;*/
+         }
+         description
+           "Bandwidth utilization that represents the actual
+            utilization of the link (i.e. as measured in the router).
+            For a bundled link, bandwidth utilization is defined to
+            be the sum of the component link bandwidth
+            utilizations.";
+       }
+     } // performance-metric-attributes
+     grouping performance-metric-normality-attributes {
+       description
+         "Link performance metric normality attributes.";
+       reference
+         "RFC7471: OSPF Traffic Engineering (TE) Metric Extensions.";
+       leaf unidirectional-delay {
+         type performance-metric-normality;
+         description "Delay normality.";
+       }
+       leaf unidirectional-min-delay {
+         type performance-metric-normality;
+         description "Minimum delay or latency normality.";
+       }
+       leaf unidirectional-max-delay {
+         type performance-metric-normality;
+         description "Maximum delay or latency normality.";
+       }
+       leaf unidirectional-delay-variation {
+         type performance-metric-normality;
+         description "Delay variation normality.";
+       }
+       leaf unidirectional-packet-loss {
+         type performance-metric-normality;
+         description "Packet loss normality.";
+       }
+       leaf unidirectional-residual-bandwidth {
+         type performance-metric-normality;
+         description "Residual bandwidth normality.";
+       }
+       leaf unidirectional-available-bandwidth {
+         type performance-metric-normality;
+         description "Available bandwidth normality.";
+       }
+       leaf unidirectional-utilized-bandwidth {
+         type performance-metric-normality;
+         description "Bandwidth utilization normality.";
+       }
+     } // performance-metric-normality-attributes
+
+     grouping performance-metric-throttle-container {
+       description
+         "A container controlling performance metric throttle.";
+       container performance-metric-throttle {
+         if-feature te-performance-metric;
+         /*must "suppression-interval >= measure-interval" {
+           error-message
+             "suppression-interval cannot be less then
+              measure-interval.";
+           description
+             "Constraint on suppression-interval and
+              measure-interval.";
+         }*/
+         description
+           "Link performance information in real time.";
+         reference
+           "RFC7471: OSPF Traffic Engineering (TE) Metric Extensions.";
+         leaf unidirectional-delay-offset {
+           type uint32 {
+             range 0..16777215;
+           }
+           description
+             "Offset value to be added to the measured delay value.";
+         }
+         leaf measure-interval {
+           type uint32;
+           default 30;
+           description
+             "Interval in seconds to measure the extended metric
+              values.";
+         }
+         leaf advertisement-interval {
+           type uint32;
+           description
+             "Interval in seconds to advertise the extended metric
+              values.";
+         }
+         leaf suppression-interval {
+           type uint32 {
+             range "1..max";
+           }
+           default 120;
+           description
+             "Interval in seconds to suppress advertising the extended
+              metric values.";
+         }
+         container threshold-out {
+           uses performance-metric-attributes;
+           description
+             "If the measured parameter falls outside an upper bound
+              for all but the min delay metric (or lower bound for
+              min-delay metric only) and the advertised value is not
+              already outside that bound, anomalous announcement will be
+              triggered.";
+         }
+         container threshold-in {
+           uses performance-metric-attributes;
+           description
+             "If the measured parameter falls inside an upper bound
+              for all but the min delay metric (or lower bound for
+              min-delay metric only) and the advertised value is not
+              already inside that bound, normal (anomalous-flag cleared)
+              announcement will be triggered.";
+         }
+         container threshold-accelerated-advertisement {
+           description
+             "When the difference between the last advertised value and
+              current measured value exceed this threshold, anomalous
+              announcement will be triggered.";
+           uses performance-metric-attributes;
+         }
+       }
+     } // performance-metric-throttle-container
+
+     grouping te-link-augment {
+       description
+         "Augmentation for TE link.";
+
+       container te {
+         presence "TE support.";
+         description
+           "Indicates TE support.";
+
+         container config {
+           description
+             "Configuration data.";
+           uses te-link-config;
+         } // config
+         container state {
+           config false;
+           description
+             "Operational state data.";
+           uses te-link-config;
+           uses te-link-state-derived;
+         } // state
+       } // te
+     } // te-link-augment
+
+     grouping te-link-config {
+       description
+         "TE link configuration grouping.";
+       choice bundle-stack-level {
+         description
+           "The TE link can be partitioned into bundled
+            links, or component links.";
+         case bundle {
+           container bundled-links {
+             description
+               "A set of bundled links.";
+             reference
+               "RFC4201: Link Bundling in MPLS Traffic Engineering
+               (TE).";
+             list bundled-link {
+               key "sequence";
+               description
+                 "Specify a bundled interface that is
+                  further partitioned.";
+               leaf sequence {
+                 type uint32;
+                 description
+                   "Identify the sequence in the bundle.";
+               }
+               leaf src-tp-ref {
+                 type nt:tp-id;
+                 description
+                   "Reference to another TE termination point on the
+                    same souruce node.";
+               }
+               leaf des-tp-ref {
+                 type nt:tp-id;
+                 description
+                   "Reference to another TE termination point on the
+                    same destination node.";
+               }
+             } // list bundled-link
+           }
+         }
+         case component {
+           container component-links {
+             description
+               "A set of component links";
+             list component-link {
+               key "sequence";
+               description
+                 "Specify a component interface that is
+                  sufficient to unambiguously identify the
+                  appropriate resources";
+
+               leaf sequence {
+                 type uint32;
+                 description
+                   "Identify the sequence in the bundle.";
+               }
+               leaf src-interface-ref {
+                 type string;
+                 description
+                   "Reference to component link interface on the
+                    source node.";
+               }
+               leaf des-interface-ref {
+                 type string;
+                 description
+                   "Reference to component link interface on the
+                    destinatioin node.";
+               }
+             }
+           }
+         }
+       } // bundle-stack-level
+
+       leaf-list te-link-template {
+         if-feature template;
+         type te-template-name;
+         description
+           "The reference to a TE link template.";
+       }
+       uses te-link-config-attributes;
+     } // te-link-config
+
+     grouping te-link-config-attributes {
+       description
+         "Link configuration attributes in a TE topology.";
+       container te-link-attributes {
+         description "Link attributes in a TE topology.";
+         uses sch:schedules;
+         leaf access-type {
+           type te-link-access-type;
+           description
+             "Link access type, which can be point-to-point or
+              multi-access.";
+         }
+         leaf is-abstract {
+           type empty;
+           description "Present if the link is abstract.";
+         }
+         leaf name {
+           type string;
+           description "Link Name.";
+         }
+         container underlay {
+           if-feature te-topology-hierarchy;
+           presence
+             "Indicates the underlay exists for this link.";
+           description "Attributes of the te-link underlay.";
+           reference
+             "RFC4206: Label Switched Paths (LSP) Hierarchy with
+              Generalized Multi-Protocol Label Switching (GMPLS)
+              Traffic Engineering (TE)";
+
+           uses te-link-underlay-attributes;
+         } // underlay
+         leaf admin-status {
+           type te-admin-status;
+           description
+             "The administrative state of the link.";
+         }
+
+         uses performance-metric-throttle-container;
+         uses te-link-info-attributes;
+       } // te-link-attributes
+     } // te-link-config-attributes
+
+     grouping te-link-info-attributes {
+       description
+         "Advertised TE information attributes.";
+       leaf link-index {
+         type uint64;
+         description
+           "The link identifier.  If OSPF is used, this represents an
+            ospfLsdbID.  If IS-IS is used, this represents an isisLSPID.
+            If a locally configured link is used, this object represents
+            a unique value, which is locally defined in a router.";
+       }
+       leaf administrative-group {
+         type te-types:admin-groups;
+         description
+           "Administrative group or color of the link.
+            This attribute covers both administrative group (defined in
+            RFC3630, RFC5329, and RFC5305), and extended administrative
+            group (defined in RFC7308).";
+       }
+       leaf max-link-bandwidth {
+         type decimal64 {
+           /*fraction-digits 2;*/
+         }
+         description
+           "Maximum bandwidth that can be seen on this link in this
+            direction. Units in bytes per second.";
+         reference
+           "RFC3630: Traffic Engineering (TE) Extensions to OSPF
+            Version 2.
+            RFC5305: IS-IS Extensions for Traffic Engineering.";
+       }
+       leaf max-resv-link-bandwidth {
+         type decimal64 {
+           /*fraction-digits 2;*/
+         }
+         description
+           "Maximum amount of bandwidth that can be reserved in this
+            direction in this link. Units in bytes per second.";
+         reference
+           "RFC3630: Traffic Engineering (TE) Extensions to OSPF
+            Version 2.
+            RFC5305: IS-IS Extensions for Traffic Engineering.";
+       }
+       list unreserved-bandwidth {
+         key "priority";
+         max-elements "8";
+         description
+           "Unreserved bandwidth for 0-7 priority levels. Units in
+            bytes per second.";
+         reference
+           "RFC3630: Traffic Engineering (TE) Extensions to OSPF
+            Version 2.
+            RFC5305: IS-IS Extensions for Traffic Engineering.";
+         leaf priority {
+           type uint8 {
+             range "0..7";
+           }
+           description "Priority.";
+         }
+         leaf bandwidth {
+           type decimal64 {
+             /*fraction-digits 2;*/
+           }
+           description
+             "Unreserved bandwidth for this level.";
+         }
+       }
+       leaf te-default-metric {
+         type uint32;
+         description
+           "Traffic Engineering Metric.";
+       }
+       container performance-metric {
+         if-feature te-performance-metric;
+         description
+           "Link performance information in real time.";
+         reference
+           "RFC7471: OSPF Traffic Engineering (TE) Metric Extensions.";
+         container measurement {
+           description
+             "Measured performance metric values. Static configuration
+              and manual overrides of these measurements are also
+              allowed.";
+           uses performance-metric-attributes;
+         }
+         container normality
+         {
+           description
+             "Performance metric normality values.";
+           uses performance-metric-normality-attributes;
+         }
+       }
+       leaf link-protection-type {
+         type enumeration {
+           enum "unprotected" {
+             description "Unprotected.";
+           }
+           enum "extra-traffic" {
+             description "Extra traffic.";
+           }
+           enum "shared" {
+             description "Shared.";
+           }
+           enum "1-for-1" {
+             description "One for one protection.";
+           }
+           enum "1-plus-1" {
+             description "One plus one protection.";
+           }
+           enum "enhanced" {
+             description "Enhanced protection.";
+           }
+         }
+         description
+           "Link Protection Type desired for this link.";
+         reference
+           "RFC4202: Routing Extensions in Support of
+            Generalized Multi-Protocol Label Switching (GMPLS).";
+       }
+       list interface-switching-capability {
+         key "switching-capability";
+         description
+           "List of Interface Switching Capabilities Descriptors (ISCD)
+            for this link.";
+         reference
+           "RFC3471: Generalized Multi-Protocol Label Switching (GMPLS)
+            Signaling Functional Description.
+            RFC4203: OSPF Extensions in Support of Generalized
+            Multi-Protocol Label Switching (GMPLS).";
+         leaf switching-capability {
+           type string;
+           description
+             "Switching Capability for this interface.";
+         }
+         leaf encoding {
+           type string;
+           description
+             "Encoding supported by this interface.";
+         }
+         list max-lsp-bandwidth {
+           key "priority";
+           max-elements "8";
+           description
+             "Maximum LSP Bandwidth at priorities 0-7.";
+           leaf priority {
+             type uint8 {
+               range "0..7";
+             }
+             description "Priority.";
+           }
+           leaf bandwidth {
+             type decimal64 {
+               /*fraction-digits 2;*/
+             }
+             description
+               "Max LSP Bandwidth for this level";
+           }
+         }
+         container time-division-multiplex-capable {
+           when "../switching-capability = 'TDM'" {
+             description "Valid only for TDM";
+           }
+           description
+             "Interface has time-division multiplex capabilities.";
+
+           leaf minimum-lsp-bandwidth {
+             type decimal64 {
+               /*fraction-digits 2;*/
+             }
+             description
+               "Minimum LSP Bandwidth. Units in bytes per second.";
+           }
+           leaf indication {
+             type enumeration {
+               enum "standard" {
+                 description
+                   "Indicates support of standard SONET/SDH.";
+               }
+               enum "arbitrary" {
+                 description
+                   "Indicates support of arbitrary SONET/SDH.";
+               }
+             }
+             description
+               "Indication whether the interface supports Standard or
+                Arbitrary SONET/SDH";
+           }
+         }
+         list interface-adjustment-capability {
+           key "upper-sc";
+           description
+             "List of Interface Adjustment Capability Descriptors (IACD)
+              for this link.";
+           reference
+             "RFC6001: Generalized MPLS (GMPLS) Protocol Extensions
+              for Multi-Layer and Multi-Region Networks (MLN/MRN).";
+           leaf upper-sc {
+             type string;
+             description
+               "Switching Capability for this interface.";
+           }
+           leaf upper-encoding {
+             type string;
+             description
+               "Encoding supported by this interface.";
+           }
+           list max-lsp-bandwidth {
+             key "priority";
+             max-elements "8";
+             description
+               "Maximum LSP Bandwidth at priorities 0-7.";
+             leaf priority {
+               type uint8 {
+                 range "0..7";
+               }
+               description "Priority.";
+             }
+             leaf bandwidth {
+               type decimal64 {
+                 /*fraction-digits 2;*/
+               }
+               description
+                 "Max LSP Bandwidth for this level.";
+             }
+           }
+         } // interface-adjustment-capability
+       } // interface-switching-capability
+       container te-srlgs {
+         description
+           "A list of SLRGs.";
+         leaf-list values {
+           type te-types:srlg;
+           description "SRLG value.";
+           reference
+             "RFC4202: Routing Extensions in Support of
+              Generalized Multi-Protocol Label Switching (GMPLS).";
+         }
+       }
+     } // te-link-info-attributes
+
+     grouping te-link-state-derived {
+       description
+         "Link state attributes in a TE topology.";
+       leaf oper-status {
+         type te-oper-status;
+         description
+           "The current operational state of the link.";
+       }
+       uses information-source-attributes;
+       list alt-information-sources {
+         key "information-source";
+         description
+           "A list of information sources learned but not used.";
+         uses information-source-attributes;
+         uses te-link-info-attributes;
+       }
+       container recovery {
+         description
+           "Status of the recovery process.";
+         leaf restoration-status {
+           type te-recovery-status;
+           description
+             "Restoration status.";
+         }
+         leaf protection-status {
+           type te-recovery-status;
+           description
+             "Protection status.";
+         }
+       }
+       container underlay {
+         if-feature te-topology-hierarchy;
+         description "State attributes for te-link underlay.";
+         uses te-link-state-underlay-attributes;
+       }
+     } // te-link-state-derived
+     grouping te-link-state-underlay-attributes {
+       description "State attributes for te-link underlay.";
+       leaf dynamic {
+         type boolean;
+         description
+           "true if the underlay is dynamically created.";
+       }
+       leaf committed {
+         type boolean;
+         description
+           "true if the underlay is committed.";
+       }
+     } // te-link-state-underlay-attributes
+
+     grouping te-link-underlay-attributes {
+       description "Attributes for  te-link underlay.";
+       reference
+         "RFC4206: Label Switched Paths (LSP) Hierarchy with
+          Generalized Multi-Protocol Label Switching (GMPLS)
+          Traffic Engineering (TE)";
+       container underlay-primary-path {
+         description
+           "The service path on the underlay topology that
+            supports this link.";
+         uses te-topology-ref;
+         list path-element {
+           key "path-element-id";
+           description
+             "A list of path elements describing the service path.";
+           leaf path-element-id {
+             type uint32;
+             description "To identify the element in a path.";
+           }
+           uses te-path-element;
+         }
+       } // underlay-primary-path
+       list underlay-backup-path {
+         key "index";
+         description
+           "A list of backup service paths on the underlay topology that
+            protect the underlay primary path. If the primary path is
+            not protected, the list contains zero elements. If the
+            primary path is protected, the list contains one or more
+            elements.";
+         leaf index {
+           type uint32;
+           description
+             "A sequence number to identify a backup path.";
+         }
+         uses te-topology-ref;
+         list path-element {
+           key "path-element-id";
+           description
+             "A list of path elements describing the backup service
+              path";
+           leaf path-element-id {
+             type uint32;
+             description "To identify the element in a path.";
+           }
+           uses te-path-element;
+         }
+       } // underlay-backup-path
+       leaf underlay-protection-type {
+         type uint16;
+         description
+           "Underlay protection type desired for this link";
+       }
+       container underlay-trail-src {
+         uses nt:tp-ref;
+         description
+           "Source TE link of the underlay trail.";
+       }
+       container underlay-trail-des {
+         uses nt:tp-ref;
+         description
+           "Destination TE link of the underlay trail.";
+       }
+     } // te-link-underlay-attributes
+
+     grouping te-node-augment {
+       description
+         "Augmentation for TE node.";
+
+       container te {
+         presence "TE support.";
+         description
+           "Indicates TE support.";
+
+         leaf te-node-id {
+           type te-node-id;
+           mandatory true;
+           description
+             "The identifier of a node in the TE topology.
+              A node is specific to a topology to which it belongs.";
+         }
+
+         container config {
+           description
+             "Configuration data.";
+           uses te-node-config;
+         } // config
+         container state {
+           config false;
+           description
+             "Operational state data.";
+
+           uses te-node-config;
+           uses te-node-state-derived;
+         } // state
+
+         list tunnel-termination-point {
+           key "tunnel-tp-id";
+           description
+             "A termination point can terminate a tunnel.";
+           leaf tunnel-tp-id {
+             type binary;
+             description
+               "Tunnel termination point identifier.";
+           }
+           container config {
+             description
+               "Configuration data.";
+             uses te-node-tunnel-termination-capability;
+           }
+
+           container state {
+             config false;
+             description
+               "Operational state data.";
+
+             uses te-node-tunnel-termination-capability;
+             leaf switching-capability {
+               type string;
+               mandatory true;
+               description
+                 "Switching Capability.";
+             }
+             leaf encoding {
+               type string;
+               mandatory true;
+               description
+                 "Encoding type.";
+             }
+           } // state
+
+         } // tunnel-termination-point
+       } // te
+     } // te-node-augment
+
+     grouping te-node-config {
+       description "TE node configuration grouping.";
+
+       leaf-list te-node-template {
+         if-feature template;
+         type te-template-name;
+         description
+           "The reference to a TE node template.";
+       }
+       uses te-node-config-attributes;
+     } // te-node-config
+
+     grouping te-node-config-attributes {
+       description "Configuration node attributes in a TE topology.";
+       container te-node-attributes {
+         description "Containing node attributes in a TE topology.";
+         uses sch:schedules;
+         leaf admin-status {
+           type te-admin-status;
+           description
+             "The administrative state of the link.";
+         }
+         uses te-node-connectivity-matrix;
+         uses te-node-info-attributes;
+       } // te-node-attributes
+     } // te-node-config-attributes
+
+     grouping te-node-config-attributes-notification {
+       description
+         "Configuration node attributes for template in a TE topology.";
+       container te-node-attributes {
+         description "Containing node attributes in a TE topology.";
+         uses sch:schedules;
+         leaf admin-status {
+           type te-admin-status;
+           description
+             "The administrative state of the link.";
+         }
+         uses te-node-connectivity-matrix-abs;
+         uses te-node-info-attributes;
+       } // te-node-attributes
+     } // te-node-config-attributes-notification
+
+     grouping te-node-config-attributes-template {
+       description
+         "Configuration node attributes for template in a TE topology.";
+       container te-node-attributes {
+         description "Containing node attributes in a TE topology.";
+         uses sch:schedules;
+         leaf admin-status {
+           type te-admin-status;
+           description
+             "The administrative state of the link.";
+         }
+         uses te-node-info-attributes;
+       } // te-node-attributes
+     } // te-node-config-attributes-template
+
+     grouping te-node-connectivity-matrix {
+       description "Connectivity matrix on a TE node.";
+       list connectivity-matrix {
+         key "id";
+         description
+           "Represents node's switching limitations, i.e. limitations
+            in interconnecting network TE links across the node.";
+         reference
+           "RFC7579: General Network Element Constraint Encoding
+            for GMPLS-Controlled Networks.";
+         leaf id {
+           type uint32;
+           description "Identifies the connectivity-matrix entry.";
+         }
+         container from {
+           leaf tp-ref {
+             type nt:tp-id;
+             description
+               "Relative reference to source termination point.";
+           }
+           description
+             "Reference to source NTP.";
+         }
+         container to {
+           leaf tp-ref {
+             type nt:tp-id;
+             description
+               "Relative reference to destination termination point.";
+           }
+           description
+             "Reference to destination NTP.";
+         }
+         leaf is-allowed {
+           type boolean;
+           description
+             "true  - switching is allowed,
+              false - switching is disallowed.";
+         }
+       }
+     } // te-node-connectivity-matrix
+
+     grouping te-node-connectivity-matrix-abs {
+       description
+         "Connectivity matrix on a TE node, using absolute
+          paths to reference termination points.";
+       list connectivity-matrix {
+         key "id";
+         description
+           "Represents node's switching limitations, i.e. limitations
+            in interconnecting network TE links across the node.";
+         reference
+           "RFC7579: General Network Element Constraint Encoding
+            for GMPLS-Controlled Networks.";
+         leaf id {
+           type uint32;
+           description "Identifies the connectivity-matrix entry.";
+         }
+         container from {
+           uses nt:tp-ref;
+           description
+             "Reference to source NTP.";
+         }
+         container to {
+           uses nt:tp-ref;
+           description
+             "Reference to destination NTP.";
+         }
+         leaf is-allowed {
+           type boolean;
+           description
+             "true  - switching is allowed,
+              false - switching is disallowed.";
+         }
+       }
+     } // te-node-connectivity-matrix-abs
+
+     grouping te-node-info-attributes {
+       description
+         "Advertised TE information attributes.";
+       leaf domain-id {
+         type uint32;
+         description
+           "Identifies the domain that this node belongs.
+            This attribute is used to support inter-domain links.";
+         reference
+           "RFC5152: A Per-Domain Path Computation Method for
+            Establishing Inter-Domain Traffic Engineering (TE)
+            Label Switched Paths (LSPs).
+            RFC5392: OSPF Extensions in Support of Inter-Autonomous
+            System (AS) MPLS and GMPLS Traffic Engineering.
+            RFC5316: ISIS Extensions in Support of Inter-Autonomous
+            System (AS) MPLS and GMPLS Traffic Engineering.";
+       }
+       leaf is-abstract {
+         type empty;
+         description
+           "Present if the node is abstract, not present if the node
+            is actual.";
+       }
+       leaf name {
+         type inet:domain-name;
+         description "Node name.";
+       }
+       leaf-list signaling-address {
+         type inet:ip-address;
+         description "Node signaling address.";
+       }
+       container underlay-topology {
+         if-feature te-topology-hierarchy;
+         description
+           "When an abstract node encapsulates a topology,
+            the attributes in this container point to said topology.";
+         uses te-topology-ref;
+       }
+     } // te-node-info-attributes
+
+     grouping te-node-state-derived {
+       description "Node state attributes in a TE topology.";
+       leaf oper-status {
+         type te-oper-status;
+         description
+           "The current operational state of the node.";
+       }
+       leaf is-multi-access-dr {
+         type empty;
+         description
+           "The presence of this attribute indicates that this TE node
+            is a pseudonode elected as a designated router.";
+         reference
+           "RFC3630: Traffic Engineering (TE) Extensions to OSPF
+            Version 2.
+            RFC1195: Use of OSI IS-IS for Routing in TCP/IP and Dual
+            Environments.";
+       }
+       uses information-source-attributes;
+       list alt-information-sources {
+         key "information-source";
+         description
+           "A list of information sources learned but not used.";
+         uses information-source-attributes;
+         uses te-node-connectivity-matrix;
+         uses te-node-info-attributes;
+       }
+     } // te-node-state-derived
+
+     grouping te-node-state-derived-notification {
+       description "Node state attributes in a TE topology.";
+       leaf oper-status {
+         type te-oper-status;
+         description
+           "The current operational state of the node.";
+       }
+       leaf is-multi-access-dr {
+         type empty;
+         description
+           "The presence of this attribute indicates that this TE node
+            is a pseudonode elected as a designated router.";
+         reference
+           "RFC3630: Traffic Engineering (TE) Extensions to OSPF
+            Version 2.
+            RFC1195: Use of OSI IS-IS for Routing in TCP/IP and Dual
+            Environments.";
+       }
+       uses information-source-attributes;
+       list alt-information-sources {
+         key "information-source";
+         description
+           "A list of information sources learned but not used.";
+         uses information-source-attributes;
+         uses te-node-connectivity-matrix-abs;
+         uses te-node-info-attributes;
+       }
+     } // te-node-state-derived-notification
+
+     grouping te-node-tunnel-termination-capability {
+       description
+         "Termination capability of a tunnel termination point on a
+          TE node.";
+
+       list termination-capability {
+         key "link-tp";
+         description
+           "The termination capabilities between
+            tunnel-termination-point and link termination-point.
+            The capability information can be used to compute
+            the tunnel path.";
+         leaf link-tp {
+           type nt:tp-id;
+           description
+             "Link termination point.";
+         }
+       } // termination-capability
+     } // te-node-tunnel-termination-capability
+
+     grouping te-path-element {
+       description
+         "A group of attributes defining an element in a TE path
+          such as TE node, TE link, TE atomic resource or label.";
+       uses te-types:explicit-route-subobject;
+     } // te-path-element
+
+     grouping te-termination-point-augment {
+       description
+         "Augmentation for TE termination point.";
+
+       container te {
+         presence "TE support.";
+         description
+           "Indicates TE support.";
+
+         leaf te-tp-id {
+           type te-tp-id;
+           mandatory true;
+           description
+             "An identifier to uniquely identify a TE termination
+              point.";
+         }
+
+         container config {
+           description
+             "Configuration data.";
+           uses te-termination-point-config;
+         } // config
+         container state {
+           config false;
+           description
+             "Operational state data.";
+           uses te-termination-point-config;
+         } // state
+       } // te
+     } // te-termination-point-augment
+
+     grouping te-termination-point-config {
+       description
+         "TE termination point configuration grouping.";
+       uses sch:schedules;
+     } // te-termination-point-config
+
+     grouping te-topologies-augment {
+       description
+         "Augmentation for TE topologies.";
+
+       container te {
+         presence "TE support.";
+         description
+           "Indicates TE support.";
+
+         container templates {
+           description
+             "Configuration parameters for templates used for TE
+              topology.";
+
+           list node-template {
+             if-feature template;
+             key "name";
+             leaf name {
+               type te-template-name;
+               description
+                 "The name to identify a TE node template.";
+             }
+             description
+               "The list of TE node templates used to define sharable
+                and reusable TE node attributes.";
+             uses template-attributes;
+             uses te-node-config-attributes-template;
+           } // node-template
+
+           list link-template {
+             if-feature template;
+             key "name";
+             leaf name {
+               type te-template-name;
+               description
+                 "The name to identify a TE link template.";
+             }
+             description
+               "The list of TE link templates used to define sharable
+                and reusable TE link attributes.";
+             uses template-attributes;
+             uses te-link-config-attributes;
+           } // link-template
+         } // templates
+       } // te
+     } // te-topologies-augment
+
+     grouping te-topology-augment {
+       description
+         "Augmentation for TE topology.";
+
+       container te {
+         presence "TE support.";
+         description
+           "Indicates TE support.";
+
+         leaf provider-id {
+           type te-global-id;
+           mandatory true;
+           description
+             "An identifier to uniquely identify a provider.";
+         }
+         leaf client-id {
+           type te-global-id;
+           mandatory true;
+           description
+             "An identifier to uniquely identify a client.";
+         }
+         leaf te-topology-id {
+           type te-topology-id;
+           mandatory true;
+           description
+             "It is presumed that a datastore will contain many
+              topologies. To distinguish between topologies it is
+              vital to have UNIQUE topology identifiers.";
+         }
+
+         container config {
+           description
+             "Configuration data.";
+           uses te-topology-config;
+         } // config
+         container state {
+           config false;
+           description
+             "Operational state data.";
+           uses te-topology-config;
+         } // state
+       } // te
+     } // te-topology-augment
+
+     grouping te-topology-config {
+       description
+         "TE topology configuration grouping.";
+       uses sch:schedules;
+       leaf preference {
+         type uint8 {
+           range "1..255";
+         }
+         description
+           "Specifies a preference for this topology. A lower number
+            indicates a higher preference.";
+       }
+     } // te-topology-config
+
+     grouping te-topology-ref {
+       description
+         "References a TE topology.";
+       leaf provider-id-ref {
+         type te-global-id;
+         description
+           "A reference to a provider-id.";
+       }
+       leaf client-id-ref {
+         type te-global-id;
+         description
+           "A reference to a client-id.";
+       }
+       leaf te-topology-id-ref {
+         type tet:te-topology-id;
+         description
+           "A reference to a te-topology-id.";
+       }
+       leaf network-id-ref {
+         type nw:network-id;
+         description
+           "A reference to a network-id in base ietf-network module.";
+       }
+     } // te-topology-ref
+
+     grouping te-topology-type {
+       description
+         "Identifies the TE topology type.";
+       container te-topology {
+         presence "Indicates TE topology.";
+         description
+           "Its presence identifies the TE topology type.";
+       }
+     } // te-topology-type
+
+     grouping template-attributes {
+       description
+         "Common attributes for all templates.";
+
+       leaf priority {
+         type uint16;
+         description
+           "The preference value to resolve conflicts between different
+            templates. When two or more templates specify values for
+            one configuration attribute, the value from the template
+            with the highest priority is used.";
+       }
+       leaf reference-change-policy {
+         type enumeration {
+           enum no-action {
+             description
+               "When an attribute changes in this template, the
+                configuration node referring to this template does
+                not take any action.";
+           }
+           enum not-allowed {
+             description
+               "When any configuration object has a reference to this
+                template, changing this template is not allowed.";
+           }
+           enum cascade {
+             description
+               "When an attribute changes in this template, the
+                configuration object referring to this template applies
+                the new attribute value to the corresponding
+                configuration.";
+           }
+         }
+         description
+           "This attribute specifies the action taken to a configuration
+            node that has a reference to this template.";
+       }
+     } // template-attributes
+
+     /*
+      * Configuration data nodes
+      */
+     augment "/nw:networks/nw:network/nw:network-types" {
+       description
+         "Introduce new network type for TE topology.";
+       uses te-topology-type;
+     }
+
+     augment "/nw:networks" {
+       description
+         "Augmentation parameters for TE topologies.";
+       uses te-topologies-augment;
+     }
+
+     augment "/nw:networks/nw:network" {
+       when "nw:network-types/te-topology" {
+         description
+           "Augmentation parameters apply only for networks with
+            TE topology type.";
+       }
+       description
+         "Configuration parameters for TE topology.";
+       uses te-topology-augment;
+     }
+
+     augment "/nw:networks/nw:network/nw:node" {
+       when "../nw:network-types/te-topology" {
+         description
+           "Augmentation parameters apply only for networks with
+            TE topology type.";
+       }
+       description
+         "Configuration parameters for TE at node level.";
+       uses te-node-augment;
+     }
+
+     augment "/nw:networks/nw:network/nt:link" {
+       when "../nw:network-types/te-topology" {
+         description
+           "Augmentation parameters apply only for networks with
+            TE topology type.";
+       }
+       description
+         "Configuration parameters for TE at link level";
+       uses te-link-augment;
+     }
+
+     augment "/nw:networks/nw:network/nw:node/"
+           + "nt:termination-point" {
+       when "../../nw:network-types/te-topology" {
+         description
+           "Augmentation parameters apply only for networks with
+            TE topology type.";
+       }
+       description
+         "Configuration parameters for TE at termination point level";
+       uses te-termination-point-augment;
+     }
+
+     /*
+      * Operational state data nodes
+      */
+
+     /*
+      * Notifications
+      */
+     notification te-node-event {
+       description "Notification event for TE node.";
+       leaf event-type {
+         type te-topology-event-type;
+         description "Event type.";
+       }
+       uses nw:node-ref;
+       uses te-topology-type;
+       uses tet:te-node-config-attributes-notification;
+       uses tet:te-node-state-derived-notification;
+     }
+
+     notification te-link-event {
+       description "Notification event for TE link.";
+       leaf event-type {
+         type te-topology-event-type;
+         description "Event type";
+       }
+       uses nt:link-ref;
+       uses te-topology-type;
+       uses tet:te-link-config-attributes;
+       uses tet:te-link-state-derived;
+     }
+
+     augment "/te-link-event/te-link-attributes/underlay" {
+       description "Add state attributes to te-link underlay.";
+       uses te-link-state-underlay-attributes;
+     }
+   }
diff --git a/utils/yangutils/src/test/resources/interfileietf/ietf-te-types.yang b/utils/yangutils/src/test/resources/interfileietf/ietf-te-types.yang
new file mode 100644
index 0000000..0962720
--- /dev/null
+++ b/utils/yangutils/src/test/resources/interfileietf/ietf-te-types.yang
@@ -0,0 +1,853 @@
+   module ietf-te-types {
+
+     namespace "urn:ietf:params:xml:ns:yang:ietf-te-types";
+
+     /* Replace with IANA when assigned */
+     prefix "te-types";
+
+     import ietf-inet-types {
+       prefix inet;
+     }
+
+     organization
+       "IETF Traffic Engineering Architecture and Signaling (TEAS)
+        Working Group";
+
+     contact
+       "WG Web:   <http://tools.ietf.org/wg/teas/>
+        WG List:  <mailto:teas@ietf.org>
+
+        WG Chair: Lou Berger
+                  <mailto:lberger@labn.net>
+
+        WG Chair: Vishnu Pavan Beeram
+                  <mailto:vbeeram@juniper.net>
+
+        Editor:   Tarek Saad
+                  <mailto:tsaad@cisco.com>
+
+        Editor:   Rakesh Gandhi
+                  <mailto:rgandhi@cisco.com>
+
+        Editor:   Vishnu Pavan Beeram
+                  <mailto:vbeeram@juniper.net>
+
+        Editor:   Himanshu Shah
+                  <mailto:hshah@ciena.com>
+
+        Editor:   Xufeng Liu
+                  <mailto:xufeng.liu@ericsson.com>
+
+        Editor:   Xia Chen
+                  <mailto:jescia.chenxia@huawei.com>
+
+        Editor:   Raqib Jones
+                  <mailto:raqib@Brocade.com>
+
+        Editor:   Bin Wen
+                  <mailto:Bin_Wen@cable.comcast.com>";
+
+     description
+       "This module contains a collection of generally
+       useful TE specific YANG data type defintions.";
+
+     revision 2016-03-20 {
+       description "Latest revision of TE generic types";
+       reference "RFC3209";
+     }
+
+     /*identity tunnel-type {
+       description
+         "Base identity from which specific tunnel types are
+         derived.";
+     }
+
+     identity tunnel-p2p {
+       base tunnel-type;
+       description
+         "TE point-to-point tunnel type.";
+     }
+
+     identity tunnel-p2mp {
+       base tunnel-type;
+       description
+         "TE point-to-multipoint tunnel type.";
+     }
+
+     identity state-type {
+       description
+         "Base identity for TE states";
+     }
+
+     identity state-up {
+       base state-type;
+       description
+         "State up";
+     }
+
+     identity state-down {
+       base state-type;
+       description
+         "State down";
+     }
+
+     identity lsp-prot-type {
+       description
+         "Base identity from which LSP protection types are
+         derived.";
+     }
+
+     identity lsp-prot-unprotected {
+       description
+         "LSP protection 'Unprotected'";
+       reference "RFC4872";
+     }
+
+     identity lsp-prot-reroute-extra {
+       description
+         "LSP protection '(Full) Rerouting'";
+       reference "RFC4872";
+     }
+
+     identity lsp-prot-reroute {
+       description
+         "LSP protection 'Rerouting without Extra-Traffic'";
+       reference "RFC4872";
+     }
+
+     identity lsp-prot-1-for-n {
+       description
+         "LSP protection '1:N Protection with Extra-Traffic'";
+       reference "RFC4872";
+     }
+
+     identity lsp-prot-unidir-1-to-1 {
+       description
+         "LSP protection '1+1 Unidirectional Protection'";
+       reference "RFC4872";
+     }
+
+     identity lsp-prot-bidir-1-to-1 {
+       description
+         "LSP protection '1+1 Bidirectional Protection'";
+       reference "RFC4872";
+     }
+
+     identity switching-capabilities {
+       description
+         "Base identity for interface switching capabilities";
+     }
+
+     identity switching-psc1 {
+       base switching-capabilities;
+       description
+         "Packet-Switch Capable-1 (PSC-1)";
+     }
+
+     identity switching-evpl {
+       base switching-capabilities;
+       description
+         "Ethernet Virtual Private Line (EVPL)";
+     }
+
+     identity switching-l2sc {
+       base switching-capabilities;
+       description
+         "Layer-2 Switch Capable (L2SC)";
+     }
+
+     identity switching-tdm {
+       base switching-capabilities;
+       description
+         "Time-Division-Multiplex Capable (TDM)";
+     }
+
+     identity switching-otn {
+       base switching-capabilities;
+       description
+         "OTN-TDM capable";
+     }
+
+     identity switching-dcsc {
+       base switching-capabilities;
+       description
+         "Data Channel Switching Capable (DCSC)";
+     }
+     identity switching-lsc {
+       base switching-capabilities;
+       description
+         "Lambda-Switch Capable (LSC)";
+     }
+
+     identity switching-fsc {
+       base switching-capabilities;
+       description
+         "Fiber-Switch Capable (FSC)";
+     }
+
+     identity lsp-encoding-types {
+       description
+         "Base identity for encoding types";
+     }
+
+     identity lsp-encoding-packet {
+       base lsp-encoding-types;
+       description
+         "Packet LSP encoding";
+     }
+
+     identity lsp-encoding-ethernet {
+       base lsp-encoding-types;
+       description
+         "Ethernet LSP encoding";
+     }
+
+     identity lsp-encoding-pdh {
+       base lsp-encoding-types;
+       description
+         "ANSI/ETSI LSP encoding";
+     }
+
+     identity lsp-encoding-sdh {
+       base lsp-encoding-types;
+       description
+         "SDH ITU-T G.707 / SONET ANSI T1.105 LSP encoding";
+     }
+
+     identity lsp-encoding-digital-wrapper {
+       base lsp-encoding-types;
+       description
+         "Digital Wrapper LSP encoding";
+     }
+
+     identity lsp-encoding-lambda {
+       base lsp-encoding-types;
+       description
+         "Lambda (photonic) LSP encoding";
+     }
+
+     identity lsp-encoding-fiber {
+       base lsp-encoding-types;
+       description
+         "Fiber LSP encoding";
+     }
+
+     identity lsp-encoding-fiber-channel {
+       base lsp-encoding-types;
+       description
+         "FiberChannel LSP encoding";
+     }
+
+     identity lsp-encoding-oduk {
+       base lsp-encoding-types;
+       description
+         "G.709 ODUk (Digital Path)LSP encoding";
+     }
+
+     identity lsp-encoding-optical-channel {
+       base lsp-encoding-types;
+       description
+         "Line (e.g., 8B/10B) LSP encoding";
+     }
+
+     identity lsp-encoding-line {
+       base lsp-encoding-types;
+       description
+         "Line (e.g., 8B/10B) LSP encoding";
+     }*/
+
+     /* TE basic features */
+     /*feature p2mp-te {
+       description
+         "Indicates support for P2MP-TE";
+     }
+
+     feature frr-te {
+       description
+         "Indicates support for TE FastReroute (FRR)";
+     }
+
+     feature extended-admin-groups {
+       description
+         "Indicates support for TE link extended admin
+         groups.";
+     }
+
+     feature named-path-affinities {
+       description
+         "Indicates support for named path affinities";
+     }
+
+     feature named-extended-admin-groups {
+       description
+         "Indicates support for named extended admin groups";
+     }
+
+     feature named-srlg-groups {
+       description
+         "Indicates support for named SRLG groups";
+     }
+
+     feature named-path-constraints {
+       description
+         "Indicates support for named path constraints";
+     }*/
+
+     grouping explicit-route-subobject {
+       description
+         "The explicit route subobject grouping";
+       choice type {
+         description
+           "The explicit route subobject type";
+         case ipv4-address {
+           description
+             "IPv4 address explicit route subobject";
+           leaf v4-address {
+             type inet:ipv4-address;
+             description
+               "An IPv4 address.  This address is
+               treated as a prefix based on the
+               prefix length value below. Bits beyond
+               the prefix are ignored on receipt and
+               SHOULD be set to zero on transmission.";
+           }
+           leaf v4-prefix-length {
+             type uint8;
+             description
+               "Length in bits of the IPv4 prefix";
+           }
+           leaf v4-loose {
+             type boolean;
+             description
+               "Describes whether the object is loose
+               if set, or otherwise strict";
+           }
+         }
+         case ipv6-address {
+           description
+             "IPv6 address Explicit Route Object";
+           leaf v6-address {
+             type inet:ipv6-address;
+             description
+               "An IPv6 address.  This address is
+               treated as a prefix based on the
+               prefix length value below.  Bits
+               beyond the prefix are ignored on
+               receipt and SHOULD be set to zero
+               on transmission.";
+           }
+           leaf v6-prefix-length {
+             type uint8;
+             description
+               "Length in bits of the IPv4 prefix";
+           }
+           leaf v6-loose {
+             type boolean;
+             description
+               "Describes whether the object is loose
+               if set, or otherwise strict";
+           }
+         }
+         case as-number {
+           leaf as-number {
+             type uint16;
+             description "AS number";
+           }
+           description
+             "Autonomous System explicit route subobject";
+         }
+         case unnumbered-link {
+           leaf router-id {
+             type inet:ip-address;
+             description
+               "A router-id address";
+           }
+           leaf interface-id {
+             type uint32;
+             description "The interface identifier";
+           }
+           description
+             "Unnumbered link explicit route subobject";
+           reference
+             "RFC3477: Signalling Unnumbered Links in
+             RSVP-TE";
+         }
+         case label {
+           leaf value {
+             type uint32;
+             description "the label value";
+           }
+           description
+             "The Label ERO subobject";
+         }
+         /* AS domain sequence..? */
+       }
+     }
+
+     grouping record-route-subobject {
+       description
+         "The record route subobject grouping";
+       choice type {
+         description
+           "The record route subobject type";
+         case ipv4-address {
+           leaf v4-address {
+             type inet:ipv4-address;
+             description
+               "An IPv4 address.  This address is
+               treated as a prefix based on the prefix
+               length value below. Bits beyond the
+               prefix are ignored on receipt and
+               SHOULD be set to zero on transmission.";
+           }
+           leaf v4-prefix-length {
+             type uint8;
+             description
+               "Length in bits of the IPv4 prefix";
+           }
+           leaf v4-flags {
+             type uint8;
+             description
+               "IPv4 address sub-object flags";
+             reference "RFC3209";
+           }
+         }
+         case ipv6-address {
+           leaf v6-address {
+             type inet:ipv6-address;
+             description
+               "An IPv6 address.  This address is
+               treated as a prefix based on the
+               prefix length value below. Bits
+               beyond the prefix are ignored on
+               receipt and SHOULD be set to zero
+               on transmission.";
+           }
+           leaf v6-prefix-length {
+             type uint8;
+             description
+               "Length in bits of the IPv4 prefix";
+           }
+           leaf v6-flags {
+             type uint8;
+             description
+               "IPv6 address sub-object flags";
+             reference "RFC3209";
+           }
+         }
+         case label {
+           leaf value {
+             type uint32;
+             description "the label value";
+           }
+           leaf flags {
+             type uint8;
+             description
+               "Label sub-object flags";
+             reference "RFC3209";
+           }
+           description
+             "The Label ERO subobject";
+         }
+       }
+     }
+
+     /*identity route-usage-type {
+       description
+         "Base identity for route usage";
+     }
+
+     identity route-include-ero {
+       base route-usage-type;
+       description
+         "Include ERO from route";
+     }
+
+     identity route-exclude-ero {
+       base route-usage-type;
+       description
+         "Exclude ERO from route";
+     }
+
+     identity route-exclude-srlg {
+       base route-usage-type;
+       description
+         "Exclude SRLG from route";
+     }
+
+     identity path-metric-type {
+       description
+         "Base identity for path metric type";
+     }
+
+     identity path-metric-te {
+       base path-metric-type;
+       description
+         "TE path metric";
+     }
+
+     identity path-metric-igp {
+       base path-metric-type;
+       description
+         "IGP path metric";
+     }
+
+     identity path-tiebreaker-type {
+       description
+         "Base identity for path tie-breaker type";
+     }
+
+     identity path-tiebreaker-minfill {
+       base path-tiebreaker-type;
+       description
+         "Min-Fill LSP path placement";
+     }
+
+     identity path-tiebreaker-maxfill {
+       base path-tiebreaker-type;
+       description
+         "Max-Fill LSP path placement";
+     }
+
+     identity path-tiebreaker-randoom {
+       base path-tiebreaker-type;
+       description
+         "Random LSP path placement";
+     }
+
+     identity bidir-provisioning-mode {
+       description
+         "Base identity for bidirectional provisioning
+         mode.";
+     }
+
+     identity bidir-provisioning-single-sided {
+       base bidir-provisioning-mode;
+       description
+         "Single-sided bidirectional provioning mode";
+     }
+
+     identity bidir-provisioning-double-sided {
+       base bidir-provisioning-mode;
+       description
+         "Double-sided bidirectional provioning mode";
+     }
+
+     identity bidir-association-type {
+       description
+         "Base identity for bidirectional association type";
+     }
+
+     identity bidir-assoc-corouted {
+       base bidir-association-type;
+       description
+         "Co-routed bidirectional association type";
+     }
+
+     identity bidir-assoc-non-corouted {
+       base bidir-association-type;
+       description
+         "Non co-routed bidirectional association type";
+     }
+
+     identity resource-affinities-type {
+       description
+         "Base identity for resource affinities";
+     }
+
+     identity resource-aff-include-all {
+       base resource-affinities-type;
+       description
+         "The set of attribute filters associated with a
+         tunnel all of which must be present for a link
+         to be acceptable";
+     }
+
+     identity resource-aff-include-any {
+       base resource-affinities-type;
+       description
+         "The set of attribute filters associated with a
+         tunnel any of which must be present for a link
+         to be acceptable";
+     }
+
+     identity resource-aff-exclude-any {
+       base resource-affinities-type;
+       description
+         "The set of attribute filters associated with a
+         tunnel any of which renders a link unacceptable";
+     }*/
+
+     typedef admin-group {
+       type binary {
+//         length 32;
+       }
+       description
+         "Administrative group/Resource class/Color.";
+     }
+
+     typedef extended-admin-group {
+       type binary;
+       description
+         "Extended administrative group/Resource class/Color.";
+     }
+
+     typedef admin-groups {
+       type union {
+         type admin-group;
+         type extended-admin-group;
+       }
+       description "TE administrative group derived type";
+     }
+
+     typedef srlg {
+       type uint32;
+       description "SRLG type";
+     }
+
+     /*identity path-computation-srlg-type {
+       description
+         "Base identity for SRLG path computation";
+     }
+
+     identity srlg-ignore {
+       base path-computation-srlg-type;
+       description
+         "Ignores SRLGs in path computation";
+     }
+
+     identity srlg-strict {
+       base path-computation-srlg-type;
+       description
+         "Include strict SRLG check in path computation";
+     }
+
+     identity srlg-preferred {
+       base path-computation-srlg-type;
+       description
+         "Include preferred SRLG check in path computation";
+     }
+
+     identity srlg-weighted {
+       base path-computation-srlg-type;
+       description
+         "Include weighted SRLG check in path computation";
+     }*/
+
+     typedef te-metric {
+       type uint32;
+       description
+         "TE link metric";
+     }
+
+     typedef topology-id {
+       type string {
+         pattern '/?([a-zA-Z0-9\-_.]+)(/[a-zA-Z0-9\-_.]+)*';
+       }
+       description
+         "An identifier for a topology.";
+     }
+
+     /**
+      * TE tunnel generic groupings
+      **/
+
+     /* Tunnel path selection parameters */
+     grouping tunnel-path-selection {
+       description
+         "Tunnel path selection properties grouping";
+       container path-selection {
+         description
+           "Tunnel path selection properties container";
+         leaf topology {
+           type te-types:topology-id;
+           description
+             "The tunnel path is computed using the specific
+             topology identified by this identifier";
+         }
+         leaf cost-limit {
+           type uint32 {
+             range "1..4294967295";
+           }
+           description
+             "The tunnel path cost limit.";
+         }
+         leaf hop-limit {
+           type uint8 {
+             range "1..255";
+           }
+           description
+             "The tunnel path hop limit.";
+         }
+         leaf metric-type {
+           type string;
+           description
+             "The tunnel path metric type.";
+         }
+         leaf tiebreaker-type {
+           type string;
+           description
+             "The tunnel path computation tie breakers.";
+         }
+         leaf ignore-overload {
+           type boolean;
+           description
+             "The tunnel path can traverse overloaded node.";
+         }
+         uses tunnel-path-affinities;
+         uses tunnel-path-srlgs;
+       }
+     }
+
+     grouping tunnel-path-affinities {
+       description
+         "Path affinities grouping";
+       container tunnel-path-affinities {
+         if-feature named-path-affinities;
+         description
+           "Path affinities container";
+         choice style {
+           description
+             "Path affinities representation style";
+           case values {
+             leaf value {
+               type uint32 {
+                 range "0..4294967295";
+               }
+               description
+                 "Affinity value";
+             }
+             leaf mask {
+               type uint32 {
+                 range "0..4294967295";
+               }
+               description
+                 "Affinity mask";
+             }
+           }
+           case named {
+             list constraints {
+               key "usage";
+               leaf usage {
+                 type string;
+                 description "Affinities usage";
+               }
+               container constraint {
+                 description
+                   "Container for named affinities";
+                 list affinity-names {
+                   key "name";
+                   leaf name {
+                     type string;
+                     description
+                       "Affinity name";
+                   }
+                   description
+                     "List of named affinities";
+                 }
+               }
+               description
+                 "List of named affinity constraints";
+             }
+           }
+         }
+       }
+     }
+
+     grouping tunnel-path-srlgs {
+       description
+         "Path SRLG properties grouping";
+       container tunnel-path-srlgs {
+         description
+           "Path SRLG properties container";
+         choice style {
+           description
+             "Type of SRLG representation";
+           case values {
+             leaf usage {
+               type string;
+               description "SRLG usage";
+             }
+             leaf-list values {
+               type te-types:srlg;
+               description "SRLG value";
+             }
+           }
+           case named {
+             list constraints {
+               key "usage";
+               leaf usage {
+                 type string;
+                 description "SRLG usage";
+               }
+               container constraint {
+                 description
+                   "Container for named SRLG list";
+                 list srlg-names {
+                   key "name";
+                   leaf name {
+                     type string;
+                     description
+                       "The SRLG name";
+                   }
+                   description
+                     "List named SRLGs";
+                 }
+               }
+               description
+                 "List of named SRLG constraints";
+             }
+           }
+         }
+       }
+     }
+
+     grouping tunnel-bidir-assoc-properties {
+       description
+         "TE tunnel associated bidirectional properties
+         grouping";
+       container bidirectional {
+         description
+           "TE tunnel associated bidirectional attributes.";
+         container association {
+           description
+             "Tunnel bidirectional association properties";
+           leaf id {
+             type uint16;
+             description
+               "The TE tunnel association identifier.";
+           }
+           leaf source {
+             type inet:ip-address;
+             description
+               "The TE tunnel association source.";
+           }
+           leaf global-source {
+             type inet:ip-address;
+             description
+               "The TE tunnel association global
+               source.";
+           }
+           leaf type {
+             type string;
+             description
+               "The TE tunnel association type.";
+           }
+           leaf provisioing {
+             type string;
+             description
+               "Describes the provisioning model of the
+               associated bidirectional LSP";
+             reference
+               "draft-ietf-teas-mpls-tp-rsvpte-ext-
+               associated-lsp, section-3.2";
+           }
+         }
+       }
+     }
+     /*** End of TE tunnel groupings ***/
+
+     /**
+      * TE interface generic groupings
+      **/
+   }
diff --git a/utils/yangutils/src/test/resources/interfileietf/ietf-yang-types.yang b/utils/yangutils/src/test/resources/interfileietf/ietf-yang-types.yang
new file mode 100644
index 0000000..9a543fa
--- /dev/null
+++ b/utils/yangutils/src/test/resources/interfileietf/ietf-yang-types.yang
@@ -0,0 +1,490 @@
+  module ietf-yang-types {
+
+    yang-version 1;
+
+    namespace
+      "urn:ietf:params:xml:ns:yang:ietf-yang-types";
+
+    prefix yang;
+
+    organization
+      "IETF NETMOD (NETCONF Data Modeling Language) Working Group";
+
+    contact
+      "WG Web:   <http://tools.ietf.org/wg/netmod/>
+    WG List:  <mailto:netmod@ietf.org>
+
+    WG Chair: David Kessens
+              <mailto:david.kessens@nsn.com>
+
+    WG Chair: Juergen Schoenwaelder
+              <mailto:j.schoenwaelder@jacobs-university.de>
+
+    Editor:   Juergen Schoenwaelder
+              <mailto:j.schoenwaelder@jacobs-university.de>";
+
+    description
+      "This module contains a collection of generally useful derived
+    YANG data types.
+
+    Copyright (c) 2013 IETF Trust and the persons identified as
+    authors of the code.  All rights reserved.
+
+    Redistribution and use in source and binary forms, with or
+    without modification, is permitted pursuant to, and subject
+    to the license terms contained in, the Simplified BSD License
+    set forth in Section 4.c of the IETF Trust's Legal Provisions
+    Relating to IETF Documents
+    (http://trustee.ietf.org/license-info).
+
+    This version of this YANG module is part of RFC 6991; see
+    the RFC itself for full legal notices.";
+
+    revision "2013-07-15" {
+      description
+        "This revision adds the following new data types:
+      - yang-identifier
+      - hex-string
+      - uuid
+      - dotted-quad";
+      reference
+        "RFC 6991: Common YANG Data Types";
+
+    }
+
+    revision "2010-09-24" {
+      description "Initial revision.";
+      reference
+        "RFC 6021: Common YANG Data Types";
+
+    }
+
+
+    typedef counter32 {
+      type uint32;
+      description
+        "The counter32 type represents a non-negative integer
+      that monotonically increases until it reaches a
+      maximum value of 2^32-1 (4294967295 decimal), when it
+      wraps around and starts increasing again from zero.
+
+      Counters have no defined 'initial' value, and thus, a
+      single value of a counter has (in general) no information
+      content.  Discontinuities in the monotonically increasing
+      value normally occur at re-initialization of the
+      management system, and at other times as specified in the
+      description of a schema node using this type.  If such
+      other times can occur, for example, the creation of
+      a schema node of type counter32 at times other than
+      re-initialization, then a corresponding schema node
+      should be defined, with an appropriate type, to indicate
+      the last discontinuity.
+
+      The counter32 type should not be used for configuration
+      schema nodes.  A default statement SHOULD NOT be used in
+      combination with the type counter32.
+
+      In the value set and its semantics, this type is equivalent
+      to the Counter32 type of the SMIv2.";
+      reference
+        "RFC 2578: Structure of Management Information Version 2
+        	  (SMIv2)";
+
+    }
+
+    typedef zero-based-counter32 {
+      type counter32;
+      default "0";
+      description
+        "The zero-based-counter32 type represents a counter32
+      that has the defined 'initial' value zero.
+
+      A schema node of this type will be set to zero (0) on creation
+      and will thereafter increase monotonically until it reaches
+      a maximum value of 2^32-1 (4294967295 decimal), when it
+      wraps around and starts increasing again from zero.
+
+      Provided that an application discovers a new schema node
+      of this type within the minimum time to wrap, it can use the
+      'initial' value as a delta.  It is important for a management
+      station to be aware of this minimum time and the actual time
+      between polls, and to discard data if the actual time is too
+      long or there is no defined minimum time.
+
+      In the value set and its semantics, this type is equivalent
+      to the ZeroBasedCounter32 textual convention of the SMIv2.";
+      reference
+        "RFC 4502: Remote Network Monitoring Management Information
+        	  Base Version 2";
+
+    }
+
+    typedef counter64 {
+      type uint64;
+      description
+        "The counter64 type represents a non-negative integer
+      that monotonically increases until it reaches a
+      maximum value of 2^64-1 (18446744073709551615 decimal),
+      when it wraps around and starts increasing again from zero.
+
+      Counters have no defined 'initial' value, and thus, a
+      single value of a counter has (in general) no information
+      content.  Discontinuities in the monotonically increasing
+      value normally occur at re-initialization of the
+      management system, and at other times as specified in the
+      description of a schema node using this type.  If such
+      other times can occur, for example, the creation of
+      a schema node of type counter64 at times other than
+      re-initialization, then a corresponding schema node
+      should be defined, with an appropriate type, to indicate
+      the last discontinuity.
+
+      The counter64 type should not be used for configuration
+      schema nodes.  A default statement SHOULD NOT be used in
+      combination with the type counter64.
+
+      In the value set and its semantics, this type is equivalent
+      to the Counter64 type of the SMIv2.";
+      reference
+        "RFC 2578: Structure of Management Information Version 2
+        	  (SMIv2)";
+
+    }
+
+    typedef zero-based-counter64 {
+      type counter64;
+      default "0";
+      description
+        "The zero-based-counter64 type represents a counter64 that
+      has the defined 'initial' value zero.
+
+
+
+
+      A schema node of this type will be set to zero (0) on creation
+      and will thereafter increase monotonically until it reaches
+      a maximum value of 2^64-1 (18446744073709551615 decimal),
+      when it wraps around and starts increasing again from zero.
+
+      Provided that an application discovers a new schema node
+      of this type within the minimum time to wrap, it can use the
+      'initial' value as a delta.  It is important for a management
+      station to be aware of this minimum time and the actual time
+      between polls, and to discard data if the actual time is too
+      long or there is no defined minimum time.
+
+      In the value set and its semantics, this type is equivalent
+      to the ZeroBasedCounter64 textual convention of the SMIv2.";
+      reference
+        "RFC 2856: Textual Conventions for Additional High Capacity
+        	  Data Types";
+
+    }
+
+    typedef gauge32 {
+      type uint32;
+      description
+        "The gauge32 type represents a non-negative integer, which
+      may increase or decrease, but shall never exceed a maximum
+      value, nor fall below a minimum value.  The maximum value
+      cannot be greater than 2^32-1 (4294967295 decimal), and
+      the minimum value cannot be smaller than 0.  The value of
+      a gauge32 has its maximum value whenever the information
+      being modeled is greater than or equal to its maximum
+      value, and has its minimum value whenever the information
+      being modeled is smaller than or equal to its minimum value.
+      If the information being modeled subsequently decreases
+      below (increases above) the maximum (minimum) value, the
+      gauge32 also decreases (increases).
+
+      In the value set and its semantics, this type is equivalent
+      to the Gauge32 type of the SMIv2.";
+      reference
+        "RFC 2578: Structure of Management Information Version 2
+        	  (SMIv2)";
+
+    }
+
+    typedef gauge64 {
+      type uint64;
+      description
+        "The gauge64 type represents a non-negative integer, which
+      may increase or decrease, but shall never exceed a maximum
+      value, nor fall below a minimum value.  The maximum value
+      cannot be greater than 2^64-1 (18446744073709551615), and
+      the minimum value cannot be smaller than 0.  The value of
+      a gauge64 has its maximum value whenever the information
+      being modeled is greater than or equal to its maximum
+      value, and has its minimum value whenever the information
+      being modeled is smaller than or equal to its minimum value.
+      If the information being modeled subsequently decreases
+      below (increases above) the maximum (minimum) value, the
+      gauge64 also decreases (increases).
+
+      In the value set and its semantics, this type is equivalent
+      to the CounterBasedGauge64 SMIv2 textual convention defined
+      in RFC 2856";
+      reference
+        "RFC 2856: Textual Conventions for Additional High Capacity
+        	  Data Types";
+
+    }
+
+    typedef object-identifier {
+      type string {
+        pattern
+          '(([0-1](\.[1-3]?[0-9]))|(2\.(0|([1-9]\d*))))(\.(0|([1-9]\d*)))*';
+      }
+      description
+        "The object-identifier type represents administratively
+      assigned names in a registration-hierarchical-name tree.
+
+      Values of this type are denoted as a sequence of numerical
+      non-negative sub-identifier values.  Each sub-identifier
+      value MUST NOT exceed 2^32-1 (4294967295).  Sub-identifiers
+      are separated by single dots and without any intermediate
+      whitespace.
+
+      The ASN.1 standard restricts the value space of the first
+      sub-identifier to 0, 1, or 2.  Furthermore, the value space
+      of the second sub-identifier is restricted to the range
+      0 to 39 if the first sub-identifier is 0 or 1.  Finally,
+      the ASN.1 standard requires that an object identifier
+      has always at least two sub-identifiers.  The pattern
+      captures these restrictions.
+
+      Although the number of sub-identifiers is not limited,
+      module designers should realize that there may be
+      implementations that stick with the SMIv2 limit of 128
+      sub-identifiers.
+
+      This type is a superset of the SMIv2 OBJECT IDENTIFIER type
+      since it is not restricted to 128 sub-identifiers.  Hence,
+      this type SHOULD NOT be used to represent the SMIv2 OBJECT
+      IDENTIFIER type; the object-identifier-128 type SHOULD be
+      used instead.";
+      reference
+        "ISO9834-1: Information technology -- Open Systems
+        Interconnection -- Procedures for the operation of OSI
+        Registration Authorities: General procedures and top
+        arcs of the ASN.1 Object Identifier tree";
+
+    }
+
+    typedef object-identifier-128 {
+      type object-identifier {
+        pattern '\d*(\.\d*){1,127}';
+      }
+      description
+        "This type represents object-identifiers restricted to 128
+      sub-identifiers.
+
+      In the value set and its semantics, this type is equivalent
+      to the OBJECT IDENTIFIER type of the SMIv2.";
+      reference
+        "RFC 2578: Structure of Management Information Version 2
+        	  (SMIv2)";
+
+    }
+
+    typedef yang-identifier {
+      type string {
+        length "1..max";
+        pattern '[a-zA-Z_][a-zA-Z0-9\-_.]*';
+        pattern
+          '.|..|[^xX].*|.[^mM].*|..[^lL].*';
+      }
+      description
+        "A YANG identifier string as defined by the 'identifier'
+       rule in Section 12 of RFC 6020.  An identifier must
+       start with an alphabetic character or an underscore
+       followed by an arbitrary sequence of alphabetic or
+       numeric characters, underscores, hyphens, or dots.
+
+       A YANG identifier MUST NOT start with any possible
+       combination of the lowercase or uppercase character
+       sequence 'xml'.";
+      reference
+        "RFC 6020: YANG - A Data Modeling Language for the Network
+        	  Configuration Protocol (NETCONF)";
+
+    }
+
+    typedef date-and-time {
+      type string {
+        pattern
+          '\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(\.\d+)?(Z|[\+\-]\d{2}:\d{2})';
+      }
+      description
+        "The date-and-time type is a profile of the ISO 8601
+      standard for representation of dates and times using the
+      Gregorian calendar.  The profile is defined by the
+      date-time production in Section 5.6 of RFC 3339.
+
+      The date-and-time type is compatible with the dateTime XML
+      schema type with the following notable exceptions:
+
+      (a) The date-and-time type does not allow negative years.
+
+      (b) The date-and-time time-offset -00:00 indicates an unknown
+          time zone (see RFC 3339) while -00:00 and +00:00 and Z
+          all represent the same time zone in dateTime.
+
+      (c) The canonical format (see below) of data-and-time values
+          differs from the canonical format used by the dateTime XML
+          schema type, which requires all times to be in UTC using
+          the time-offset 'Z'.
+
+      This type is not equivalent to the DateAndTime textual
+      convention of the SMIv2 since RFC 3339 uses a different
+      separator between full-date and full-time and provides
+      higher resolution of time-secfrac.
+
+      The canonical format for date-and-time values with a known time
+      zone uses a numeric time zone offset that is calculated using
+      the device's configured known offset to UTC time.  A change of
+      the device's offset to UTC time will cause date-and-time values
+      to change accordingly.  Such changes might happen periodically
+      in case a server follows automatically daylight saving time
+      (DST) time zone offset changes.  The canonical format for
+      date-and-time values with an unknown time zone (usually
+      referring to the notion of local time) uses the time-offset
+      -00:00.";
+      reference
+        "RFC 3339: Date and Time on the Internet: Timestamps
+         RFC 2579: Textual Conventions for SMIv2
+        XSD-TYPES: XML Schema Part 2: Datatypes Second Edition";
+
+    }
+
+    typedef timeticks {
+      type uint32;
+      description
+        "The timeticks type represents a non-negative integer that
+      represents the time, modulo 2^32 (4294967296 decimal), in
+      hundredths of a second between two epochs.  When a schema
+      node is defined that uses this type, the description of
+      the schema node identifies both of the reference epochs.
+
+      In the value set and its semantics, this type is equivalent
+      to the TimeTicks type of the SMIv2.";
+      reference
+        "RFC 2578: Structure of Management Information Version 2
+        	  (SMIv2)";
+
+    }
+
+    typedef timestamp {
+      type timeticks;
+      description
+        "The timestamp type represents the value of an associated
+      timeticks schema node at which a specific occurrence
+      happened.  The specific occurrence must be defined in the
+      description of any schema node defined using this type.  When
+      the specific occurrence occurred prior to the last time the
+      associated timeticks attribute was zero, then the timestamp
+      value is zero.  Note that this requires all timestamp values
+      to be reset to zero when the value of the associated timeticks
+      attribute reaches 497+ days and wraps around to zero.
+
+      The associated timeticks schema node must be specified
+      in the description of any schema node using this type.
+
+      In the value set and its semantics, this type is equivalent
+      to the TimeStamp textual convention of the SMIv2.";
+      reference
+        "RFC 2579: Textual Conventions for SMIv2";
+
+    }
+
+    typedef phys-address {
+      type string {
+        pattern
+          '([0-9a-fA-F]{2}(:[0-9a-fA-F]{2})*)?';
+      }
+      description
+        "Represents media- or physical-level addresses represented
+      as a sequence octets, each octet represented by two hexadecimal
+      numbers.  Octets are separated by colons.  The canonical
+      representation uses lowercase characters.
+
+      In the value set and its semantics, this type is equivalent
+      to the PhysAddress textual convention of the SMIv2.";
+      reference
+        "RFC 2579: Textual Conventions for SMIv2";
+
+    }
+
+    typedef mac-address {
+      type string {
+        pattern
+          '[0-9a-fA-F]{2}(:[0-9a-fA-F]{2}){5}';
+      }
+      description
+        "The mac-address type represents an IEEE 802 MAC address.
+      The canonical representation uses lowercase characters.
+
+      In the value set and its semantics, this type is equivalent
+      to the MacAddress textual convention of the SMIv2.";
+      reference
+        "IEEE 802: IEEE Standard for Local and Metropolitan Area
+        	  Networks: Overview and Architecture
+         RFC 2579: Textual Conventions for SMIv2";
+
+    }
+
+    typedef xpath1.0 {
+      type string;
+      description
+        "This type represents an XPATH 1.0 expression.
+
+      When a schema node is defined that uses this type, the
+      description of the schema node MUST specify the XPath
+      context in which the XPath expression is evaluated.";
+      reference
+        "XPATH: XML Path Language (XPath) Version 1.0";
+
+    }
+
+    typedef hex-string {
+      type string {
+        pattern
+          '([0-9a-fA-F]{2}(:[0-9a-fA-F]{2})*)?';
+      }
+      description
+        "A hexadecimal string with octets represented as hex digits
+      separated by colons.  The canonical representation uses
+      lowercase characters.";
+    }
+
+    typedef uuid {
+      type string {
+        pattern
+          '[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}';
+      }
+      description
+        "A Universally Unique IDentifier in the string representation
+      defined in RFC 4122.  The canonical representation uses
+      lowercase characters.
+
+      The following is an example of a UUID in string representation:
+      f81d4fae-7dec-11d0-a765-00a0c91e6bf6
+      ";
+      reference
+        "RFC 4122: A Universally Unique IDentifier (UUID) URN
+        	  Namespace";
+
+    }
+
+    typedef dotted-quad {
+      type string {
+        pattern
+          '(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])';
+      }
+      description
+        "An unsigned 32-bit number expressed in the dotted-quad
+       notation, i.e., four octets written as decimal numbers
+       and separated with the '.' (full stop) character.";
+    }
+  }  // module ietf-yang-types
+